GED Math: Making a Problem into a Formula

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 or call 1-888-880-2164.

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