profit or loss

Hey Robin,

On a question like this, you'd likely be able to use logic/answer choices to get at shortcuts. Often the GMAT gives questions where the shortcuts are so efficient that you shouldn't do the math. However, the math here should be pretty easy, if you know your fraction/percent equivalents.

9 mangoes per dollar = 11.11 cents per mango
11 mangoes per dollar = 9.09 cents per mango
10 mangoes per dollar = 10 cents per mango

If we imagine 2 and 2 mangoes, that would be 22.22 + 18.18 = 40.4 cents
If we sell those four mangoes for 10 cents each = 40 cents

Loss of .4 cents, or in percents, approximately 1 percent.

Hope that helps!

-t

P.S. If you were implying that we should do this without plugging in numbers, that would be totally crazy. This isn't a shortcut, but the real way to do the question. The algebra to solve for percent change would look like this:

(11.11x + 9.09x - 10(2x))/(11.11x + 9.09x) * 100

In other words: Difference/Original * 100 = (Cost of purchase - Cost of Sale)/(Cost of purchase) * 100

The x's will immediately cancel out, so you're left doing what I did, as if you'd plugged in 1 instead of 2.

Hope that helps!

-t

Heyo,

Iceman is absolutely right. The answer is 1%. My explanation has been edited (I originally wrote 9.9 instead of 9.09, as I meant). I still prefer plugging in a small number to a big number, as long as you know what 1/11th and 1/9th look like as decimals. : )

-t

You could conceivably know that this is the same as increasing by ten percent and decreasing by ten percent, which always results in a loss of ten percent (regardless of the order of increase and decrease).

T