A room is 24 feet long, 18 feet wide, and 9 feet high. How many square yards of wallpaper are needed to paper the four walls of the room?

You got your basic area problem, right? How do I know it’s “area”? Well, area is the space on the surface of something. Like, how much carpet covers a floor, or how many tiles on a bathroom wall. Or paint on a room. If you’re covering a surface, you’re talkin’ area. Now, how to solve it?

You got a few bumps in the road. First, you got dimensions in feet, an’ you want an answer in yards. Whenever you got different measurements in a problem, I recommend always changin’ everything to the dimensions you want in yo’ answer first off. That means, changin’ all the feet to yards. Now, there’s three feet in a yard, and dat’s jus’ somethin’ you got to know. So, to change feet into yards, divide by 3.

24 feet = 8 yards
18 feet = 6 yards
9 feet = 3 yards

Hey, you gotta know you’re on the right track when all the numbers divide out evenly! Too bad real life don’t work dat way. ‘k. So’s, now it’s important to picture what the question’s about, specially with this kinda dimension question. You got a room, 8 yards by 6 yards, and 3 yards tall.

What’s the area of the 4 walls? That’s the real question… a wallpaper or carpet or tile (or anything that goes on a flat surface) question is an area question.

So… each wall got the same height, the height of the room…3 yards (9 feet):

wall 1: 3 yards × ?
wall 2: 3 yards × ?
wall 3: 3 yards × ?
wall 4: 3 yards × ?

So, what’s the width of the walls? well, 2 walls is 8 yards long (the two walls opposite of each other on the sides of the room that’re 24 feet) and 2 walls is 6 yards long (the two walls opposite of each other on the sides of the room that’re 18 feet).

wall 1: 3 yards × 8 yards
wall 2: 3 yards × 8 yards
wall 3: 3 yards × 6 yards
wall 4: 3 yards × 6 yards

To find the area, multiply:

wall 1: 3 yards  × 8 yards = 24 square yards
wall 2: 3 yards  × 8 yards = 24 square yards
wall 3: 3 yards  × 6 yards = 18 square yards
wall 4: 3 yards  × 6 yards = 18 square yards

And to find the total, add:

24 + 24 + 18 + 18 = 48 + 36 = 84 square yards

Answer’s 84!

For more information about the GED test and GED test preparation, visit the GED Academy at http://www.passGED.com.

So, here’s somethin’ that happened. And I figure it makes a pretty good word problem, especially since it’s got to do with fractions. So, lemme explain somethin’ first. I don’t cook, generally. But my friend Liz, she cooks all the time. She says it’s better for you to eat at home, and cheaper, too, and I guess I can’t argue too much widdat. So, she says she gonna teach me how to cook, right? So, she’s showin’ me how to make pancakes.

Well, the recipe for pancakes says 1-1/2 cups flour, but I don’t got a lot of measuring cups and stuff in my kitchen, and after looking around, all I could come up with is a 1/3-cup measuring cup, which I don’t know how it got there, but there it was. So, here’s the question: how many 1/3 cups of flour do I need to put in to get 1-1/2 cups?

How’s that for a word problem?

Any ideas? How’d you set about it, d’y think?

Well, here’s how I did it. I know that 3 of the 1/3 measures will give me 1 cup. Then, I need 1/2 cup. Well, if three 1/3 cups give me a whole cup, then half of that will give me a half cup. Follow? That’s 1-1/2 of the 1/3 measures. So all together, three plus 1-1/2 is 4-1/2 of the 1/3 cup measures. So, I measure out 4 and eyeball a half of the 1/3 measure. That gives me 1-1/2 cups, but I got to get some measuring cups!! Did you figure it out?

Well, how about lookin’ at the math? What we’re really doin’ here is dividing…. how many times do 1/3 go into 1-1/2… how many 1/3rds are in 1-1/2 cups? So you could write it out:

1-1/2 ÷ 1/3 =

Now, first off, I’m going to change 1-1/2 to an improper fraction, so it’s all one fraction. 1-1/2 is the same as 3/2 (that’s 2/2 plus 1/2)… so we got:

3/2 ÷ 1/3 =

Now, to DIVIDE fractions, you gotta do a switcheroo. You turn over the second fraction, so 1/3 becomes 3/1, and you change division to multiplication…

3/2 × 3/1 =

Both those steps just make the problem easier. Now, to multiply two fractions, you multiply across the top (3 × 3 = 9) to get the top, and multiply across the bottom (2 × 1 = 2) to get the bottom:

3/2 × 3/1 = 9/2

How much is 9/2? 2 goes into 9 four times, with 1 left over:

3/2 × 3/1 = 9/2 = 4-1/2

Four and a half! Same as I got just by thinkin’ it through. How’s that for some math?

How’d you do? Be sure to send me any GED problems you havin’ trouble with!

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com.

I have a question about the metric system. How do I add Grams and kilograms and milligrams, and decagrams together?

Ex.
Add: 3.45g, 0.06kg, 0.67g, 690mg, 2dg?

Hey! Yeah, excellent question. I got a article about the metric system you might wanna take a look at, to get some metric system basics… it’s at: http://www.passged.com/student_blogs/curtis/2008/07/29/ged-math-the-metric-system/

You can see the prefixes… beginnings of the words… all have meanings in the metric system. So, “grams” is just the basic measure of weight… “kilograms” is 1000 grams (kilo- = 1000), “milligrams” is 1/1000th of a gram (milli- = .001), and “decagrams” is 10 grams (deca- = 10).

First thing you wanna ask is, what do you want the answer in? Grams? Or something else? Usually the question’ll tell you, but if it don’t, choose one. In your question, I’m goin for the basic measure… grams. Two numbers is already in grams, so that makes it easier.

3.45g + 0.06kg + 0.67g + 690mg + 2dg =

So, once you figure out what you want the answer in, you gotta convert all the measures to the same thing… whatever you want the answer in… in this case, grams.

The cool thing about the metric system is, all you got to do to convert is move the decimal places. So, to change 0.06kg into grams, you multiply by 1000… which is the same as moving the decimal 3 places to the right. (You can remember cuz 1000 got 3 zeros.) So, 0.06kg is really 60 grams…

3.45g + 0.06kg + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 690mg + 2dg

So, the next one to change is 690mg. Same deal. “Milli” means 1/1000th, or .001 of a gram. So, you divide 690 by 1000 (or multiply by .001–hey, it’s the same thing!) But the easy part is, either one means moving the decimal 3 to the left (3 zeros in 1/1000, but since it’s a fraction, the decimal goes to the left instead of the right). So, 690mg = .69 grams

3.45g + 0.06kg + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 0.69g + 2dg

One more… decagrams. You guessed it. Multiply by 10. 2×10=20. Well, it’s the same thing… move the decimal point (the invisible one at the end of any whole number, like 2 = 2.0) over one to the right, cuz 10 got 1 zero. So, 2dg = 20 grams.

3.45g + 0.06kg + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 0.69g + 2dg = 2.45g + 60g + 0.67g + 0.69g + 20g

Now, all you got is grams. So… jus’ add. 2.45 + 60 = 62.45 + .67 = 63.12 + .69 = 63.81 + 20 = 83.81

Remember, it’s in grams… so that’s 83.81 grams.

Any time somthin’s in different measures (inches and feet, grams and kilograms, ounces and pounds, whatever), the first thing you gotta do is make all the measurements the same… an’ to make your life easier, make ‘em all whatever you want the answer in. Then on, it’s all basic math!

Good studyin’!

Curtis

For more information about the GED and GED test preparation, visit The GED Academy at http://www.passGED.com.

Truth is, most countries got the metric system cuz it’s easier. Yeah, that’s right… it’s easier. Hey, anything that makes things easier is okay by me, right? It can be hard to change over… that’s the problem. Think about all the highway signs that’d haveta change from miles to kilometers. Think of all the packaging that’d have to change from quarts to liters. Sounds like a big deal. But with all the other countries selling things in liters or grams, well, you can’t escape it. We got a global world, right? So the metric system comes creepin’ in, like with 2-liters. They sell ‘em that way so they don’t have to make 2 kindsa bottles, one for the U.S. an’ one for everyone else. True dat. Since there’s metric measurements all over the place, you gotta know it for the GED.

So, what’d'ya need to know about the metric system? I’m tellin’ you, it’s easy. You jus’ gotta know a few things…

For measuring length (like how tall you are), you got meters. A meter is about how far a doorknob is from the floor.

For measuring weight (like how much you weigh), you got grams. A nickel weighs about 5 grams.

For measuring volume (like how much is in a soda bottle), you got liters. A 2-liter bottle is 2 liters. No kiddin’.

So those are, like, your basic measurements. You got a pretty good idea how much they are, right? Well, lots of stuff is bigger and smaller, so you gotta make bigger and smaller units to measure stuff with.

Here’s how it’s done. In the metric system, they add prefixes to the words…that’s another part of the word before the main word, like kilogram or centimeter. See how they got “meter” and “gram” in the word? The prefix, like kilo- or centi- tells you how many grams or meters you’re measurin’. An they go up an’ down by factors of 10. A factor means multiplying or dividing. So, a decimeter is a meter divided by 10 (1/10 of a meter), and a decameter is a meter multiplied by 10. Here are all the prefixes and what they mean:

See how from milli- all the way up to kilo- they change by movin’ the decimal one place? That’s the beauty. You can change a number from milligrams to kilograms by jus’ movin’ the decimal. Watch this.

Say I got 403,495 grams. How many kilograms do I got? Well,  kilograms is 3 steps up from grams. So, I’m gonna move the decimal point (from the end, after the 5), 3 places to the left.

403,495 grams = 403.495 kilograms

That’s a lot easier than inches to miles, right? Cuz you just gotta move the decimal place. Got a metric system question you want me to answer? Or, any kinda measurement? Seriously, leave a comment, or e-mail curtis@passGED.com.

For more information about the GED test or GED test preparation, visit The GED Academy at http://www.passGED.com or call 1-888-880-2164.

Look my only problem with this whole G.E.D test are the word problems that involve measurements and precentages….. They stump me really bad and I just get so frustrated and give up on it…I need some advice on how to solve these problems…They really confuse me and the more and more I try the more frustrated I get at myself cause I just cannont solve them….If someone could give me some advice it would be much appreciated. Thanks -Kandyce

Hey, Kandyce. The GED has all kindsa word problems. So, the first thing is figurin’ out what they’re asking, then doin the math. Of course. Measurements and percentages is actually a lot of stuff, but let me walk thru a couple of examples, and if you have some other problems you’re havin’ trouble with, send ‘em to me, and I’ll work them out to show you how I did it.

Okay, here’s an example problem with percents, like you might get on the GED.

A bookcase is on sale for $440. The sale is 20% off the regular price. What is the regular price of the bookcase?

So, I look at a problem like this, an’ I got to figure out what it’s askin’ for. Can’t do the math if you don’t know what math it wants you to do! So, I start by takin’ the information out of the problem. There’s a sale price…It also says the sale is 20% off. So that’s the information I got to work with:

Sale price = $440

Sale = 20% off

So, the next step is to ask what’s it askin’? It’s askin’ for the regular price. That’s what I’m trying to find, so I’ll call it “x”.

Sale price = $440

Sale = 20% off

Regular price = x

Now, how do I make this stuff into an equation I can solve? How are these numbers related to each other? Cuz that’s what an equation is, it tells the relationships between different numbers.

How do you get the sale price from a regular price? Well, first you’ve got to figure what amount is the percent off, then subtract that from the regular price, right? So, if it’s $100 and it’s 20% off, then 20% of (times) $100 = $20, and $100 – $20 is $80… so the sale price is $80. So, I need to put that relationship in an equation…with “x” for the regular price.

x – (x × 20%) = $440

Yikes! That looks like a pain to solve. So, is there any easier way to think of it? Well, if the sale is 20% off the original, then the sale price is really 80% of the original price, right? I mean, if you take away 20% from any number, what have you got left? 80% of the original number. So, another way to say x – (x × 20%) is x × 80%.

On the test, use your common sense to try to put things the easiest way! But for now, let’s figure that out with math, so you can see it’s true. The first thing I’m gonna do is change 20% to .2 Remember, to change a percent to a decimal, just move the decimal place over two to the left, so 20.0% = .200 or just plain .2

x – (x × 20%) = x – (x × .20)

And x × .20 = .2x, since if you’re multiplying a number by a variable, just put the number and variable next to each other. Easy.

x – (x × 20%) = x – (x × .20) = x – .2x

And how do you subtract? Well, x is really 1 times x. So you subtract .2 from 1 and get… .8x Yes, that’s the same as 80% of x.

x – (x × 20%) = x – (x × .20) = x – .2x = 1x – .2x = .8x, or 80% of x

But you can use your common sense. If something’s 20% off, the sale price is 80% of the original. If it’s 15% off, the sale price is 85% of the original. If it’s 30% off, the sale price is 70% of the original. So, the sale price ($440) is 80% of (times) x.

.8x = $440

Now, that’s not too hard. x = $440 divided by .8, or $4400 divided by 8.

x = $440/.8 = $4400/8 = $550

That’s not too hard… 8 into 40 is 5…then 8 into 40 again is 5… with 0 left at the end. $550 is the answer.

Did you follow all that? It’s easy to get mixed up with those word problems, you just got to think them through…really figure out what they’re askin’. Here’s a website where you can practice more percent problems:

http://www.saab.org/mathdrills/percent.cgi

Okay, here’s one with measurements. Here’s the trick with measurement…stuff’s not always in the same type of measure! Yo, you know they tryin’ to trick you with that stuff. So, you get a problem like this:

Joe is out in the park practicing hitting a baseball. He’s aiming at a tree 120 yards away. He hits the ball 50 yards, 5 feet, 3 inches. He hits another ball 62 yards, 8 feet, 6 inches. In feet, how much closer is his second ball to his goal than the first ball?

Okay, feet, yards inches. Three different kinds of measurements! Yuck. But you gotta deal with it, y’know? Okay, so I start the same way, what info do I got?

tree = 120 yards

ball 1 = 50 yards, 5 feet, 3 inches

ball 2 = 62 yards, 8 feet, 6 inches

First thing I’m gonna do is change everything to feet. That’s what the answer wants, it says “IN FEET,” so if I change everything to feet now, it’s not gonna screw me up later. Seriously, if you remember one thing about measurement word problems, make it to CHANGE ALL MEASUREMENTS TO WHAT YOU WANT YOUR ANSWER IN FIRST THING.

A yard = 3 feet, so yards I multiply by 3.

tree = 120 yards = 360 feet

ball 1 = 50 yards, 5 feet, 3 inches = 150 feet + 5 feet + 3 inches = 155 feet, 3 inches

ball 2 = 62 yards, 8 feet, 6 inches = 186 feet + 8 feet + 6 inches = 194 feet, 6 inches

Now, I got to change inches to fractions of a foot. Since one foot is 12 inches, I divide the number of inches by 12.

tree = 360 feet
ball 1 = 155 feet, 3 inches = 155 feet + 3/12 feet = 155 feet + 1/4 feet = 155-1/4 feet

ball 2 = 194 feet, 6 inches = 194 feet + 6/12 feet = 194 feet + 1/2 feet = 194-1/2 feet

Now we’re getting somewhere. But I got to go back and ask the big question: what exactly do they want to know? They want to know how much CLOSER the second ball is. This is about COMPARING THE LENGTHS. That is, what’s the difference between the first ball and the second ball? Heck, I don’t even need to know the distance of the tree. I just got to subtract…

Distance closer = ball 2 – ball 1

Distance closer = 194-1/2 feet – 155-1/4 feet = 39-1/4 feet

That’s the answer! Pretty easy, once you get it all in feet and figure out what they want. Now, there’s lots of types of measurements, and knowing how to change (or convert, as they say in math) one type of measurement like yards into another like feet is important. So, here’s some websites to help with that:

http://www.mathleague.com/help/metric/metric.htm

http://www.quiz-tree.com/Units_of_Measurement_main.html

http://www.mce.k12tn.net/measurement/measurement_chart.htm

Hope this helps! Good luck gettin’ that GED. Seriously, you can pass the GED math test!

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com.