Problem Solving

LUANDATO wrote:If apples cost x dollars per m dozen, how many dollars will it cost to buy n apples?

A. xn/(12m)
B. xn/m
C. m/(xn)
D. 12m/(xn)
E. 12mn/x

The OA is A.

I don't have it clear. Can any expert explain this PS question please? Thanks.

We have apples cost x dollars per m dozen, thus apples cost x dollars per 12*m.

Thus, the cost of an apple = x/(12m)

Thus, the cost of n apples =[spoiler] xn/(12m)[/spoiler]

The correct answer: A

Hope this helps!

-Jay

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Aside: The GMAT test-makers do not expect students to know that 1 dozen = 12

Cheers,
Brent

Hi LUANDATO,

We're told that apples cost X dollars per M dozen. We're asked for the cost (in dollars) to buy N apples. This question can be solved by TESTing VALUES.

To start, a 'dozen' is 12, so it would make sense to choose a value for X that is a multiple of 12....
IF....
X=12
M=2
We're spending $12 to buy (2)(12) = 24 apples, which gives us a cost of $0.50/apple
N = 4
Thus, the cost of 4 apples is (4)($0.50) = $2. Thus, we're looking for an answer that equals 2 when we plug X=12, M=2 and N=4 into the answers. There's only one answer that matches...

Final Answer: A

GMAT assassins aren't born, they're made,
Rich

LUANDATO wrote:If apples cost x dollars per m dozen, how many dollars will it cost to buy n apples?

A. xn/(12m)
B. xn/m
C. m/(xn)
D. 12m/(xn)
E. 12mn/x

The cost of apples is x/m dollars/dozen or x/(12m) dollars/apple.

Since cost = unit price x quantity, n apples will cost x/(12m) * n = xn/(12m).

Answer: A