Ted's electronics

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Ted's electronics

by Osirus@VeritasPrep » Fri May 28, 2010 7:36 am
Ted owns an electronics business and is calculating the price of a certain group of microwaves in the inventory he purchased. If the total price of m equally priced microwaves was $18,000, what was the price per microwave in the inventory?

(1) If the price per microwave in Ted's inventory had been $10 more, the total price of the m microwaves would have been $5,000 more.

(2) If the price per microwave in Ted's inventory had been $9 less, the total price of the m microwaves would have been 25 percent less

OA [spoiler]D I'm not so much interested in the answer, could someone show me how to set up the equations for each statement and solve it all the way through? I set up statement one like this

18,000/m = 23,000. Why is that incorrect? Help me to translate the word problem if you can. Thanks in advance.[/spoiler]
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by Rich@VeritasPrep » Fri May 28, 2010 7:55 am
If we assign the variable p to the price per microwave, then the prompt basically boils down to:

pm = 18000. p = ?

This is because (price per microwave)*(number of microwaves) yields total cost. So if we know what m is, we can definitely find p.

Statement (1) actually looks like this:

(p + 10)*m = 18000+5000

This is because the price per microwave is now $10 greater, and we multiply that by m to get the new total of 23000.

(p + 10)*m = 18000+5000

pm + 10m = 23000 (by distribution)

18000 + 10m = 23000 (substitute 18000 for pm)

You now have one linear equation and one variable. You can definitely find m, and thus find p. SUFFICIENT


Statement (2) looks like this:

(p - 9)*m = .75*(18000)

Don't even worry about the right side of the equation:

pm - 9m = .75*(18000)

18000 - 9m = .75*(18000)

Again, one linear equation and one variable. You can find m, and thus find p. SUFFICIENT
Last edited by Rich@VeritasPrep on Fri May 28, 2010 8:29 am, edited 1 time in total.
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by Osirus@VeritasPrep » Fri May 28, 2010 8:04 am
Thanks for the response. One more question. Why can't we sub in 18,000/m for p? Shouldn't they be functionally the same?
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by Rich@VeritasPrep » Fri May 28, 2010 8:33 am
18000/m does indeed equal p ... but remember, p is the CURRENT price per unit, the price for which you're trying to find the value.

Each of the statements involves a NEW price per unit, a theoretical price per unit. Therefore, each of these hypothetical prices per unit is a value different from p.

I think you might have applied the formula forgetting to take into account that you can't use the variable p twice, if two different quantities are involved.

However, if you used p1 and p2, that might work ... but that's more work than you need to do for this problem :)

Make sense? Let me know if I can help anymore.
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by Osirus@VeritasPrep » Fri May 28, 2010 8:35 am
Thanks that helps tremendously.
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by puneetgangrade » Mon Nov 10, 2014 4:40 am
My doubt is driven by the explanation of this question in Veritas Data Sufficiency book, Q#72.

According to the book - "Though we get the value of P and M using the statement(1) and question stem, and when we start examining the statement(2), and reach to a one variable linear equation, why is it said that we need not further find the value of the variable ?"

In statement(2), what if the value of the variable after solving turns out to be different from the one found using statement(1) ?

Won't that contradict the answer ?

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by GMATGuruNY » Mon Nov 10, 2014 4:52 am
Ted owns an electronics business and is calculating the price of a certain group of microwaves in the inventory he purchased. If the total price of m equally priced microwaves was $18,000, what was the price per microwave in the inventory?

(1) If the price per microwave in Ted's inventory had been $10 more, the total price of the m microwaves would have been $5,000 more.

(2) If the price per microwave in Ted's inventory had been $9 less, the total price of the m microwaves would have been 25 percent less
Price per microwave = (total price)/(number of microwaves) = 18000/m.

Question stem, rephrased:
What is the value of m?

Statement 1:
m = (total price increase)/(price increase per microwave) = 5000/10 = 500.
SUFFICIENT.

Statement 2:
Total price decrease = 25% of 18,000 = 4500.
m = (total price decrease)/(price decrease per microwave) = 4500/9 = 500.
SUFFICIENT.

The correct answer is D.
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