Yo! Here’s one thing the GED math test definitely asks you to do: turn a word problem into a formula. Sometimes the GED test doesn’t ask you to solve the problem. It just asks you to look at a bunch of formulas and figure out which one’s the right one. Well, at least you don’t hafta solve it. It’s pretty useful to know, too, cuz it helps you solve other word problems. It’s one of the steps you gotta take to figure things out.
So, let’s try walkin’ thru one.
Jerry wants to buy twelve pizzas. The pizza place has a discount special, where you buy 2 pizzas and get the third 1/2 off. If P is the price of a pizza, which formula shows the price of twelve pizzas?
A) 12P/2 + 2P
B) 1/2 x 12P
C) 12P – .5P
D) 8P + .5(4P)
Okay, so what do these formulas really mean? Let’s work it from the formulas, to see if they match up with the question. P is the price of pizzas. So, the first formula means:
12P/2 + 2P means 12 pizzas, divided by 2, plus 2 pizzas. So, twelve pizzas are half off (that’s the divided by 2), and 2 pizzas are full price. That ain’t right. He’s buyin’ twelve pizzas, not 14, and he’s not gonna get half off of 12 of them.
Let’s try the next one. 1/2 x 12P means 1/2 off of 12 pizzas. Well, that’s not right. Only every third pizza is half off.
How ’bout the next one? 12P – .5P means twelve pizzas minus the price of half a pizza. That’s only one pizza being half off. That’s not right. He oughtta have more than that off his total.
Only one left. 8P + .5(4P) means 8 pizzas plus half of 4 pizzas. Point-five means half just like a fraction. So, is that right? If it’s buy 2 get 1 half off, there should be twice as many full price pizzas as half price pizzas. So there are. 8 is twice 4. So for every 2 full-price pizza, he pays half for one other pizza. And there should be 12 pizzas all together. And there are. 8 pizzas and 4 half-price pizzas, that’s 12. There’s your answer.
Let me know if you’ve got any questions.
For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passGED.com or call 1-888-880-2164.
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4 users responded in this post
[...] The GED tests your ability to understand math formulas by seeing if you can choose the right formula to represent a word problem. This week, Curtis walks you through a math formula question. [...]
Hello again , Curtis !
I came across another problem and can’t figure out how to approach it . It is as follows :
If x= y-3 and y=z^2, what is x in terms of z?
I think this involves the use of exponents stuff but I can’t make it up to work for me !
Let me know man !
Zaher
Hello , Curtis ,
Can you show me how you work with this one ?
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?
Thanks ,
Zaher
Hey, yeah. You got your basic area problem, right? But you got a few bumps in the road. First, you got dimensions in feet, an’ you want an answer in yards. 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 x ?
wall 2: 3 yards x ?
wall 3: 3 yards x ?
wall 4: 3 yards x ?
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 x 8 yards
wall 2: 3 yards x 8 yards
wall 3: 3 yards x 6 yards
wall 4: 3 yards x 6 yards
To find the area, multiply:
wall 1: 3 yards x 8 yards = 24 square yards
wall 2: 3 yards x 8 yards = 24 square yards
wall 3: 3 yards x 6 yards = 18 square yards
wall 4: 3 yards x 6 yards = 18 square yards
And to find the total, add:
24 + 24 + 18 + 18 = 48 + 36 = 84 square yards
Answer’s 84!
I’m gonna move this to a blog post later, too, with a picture…cuz sketchin’ it out sure can help.
Curtis
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