2002 AMC 12A Problem 2

Attempt Problem 2 of the 2002 AMC 12A below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2002 AMC 12A solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

Cindy was asked by her teacher to subtract

3

from a certain number and then divide the result by

9.

Instead, she subtracted

9

and then divided the result by

3,

giving an answer of

43.

What would her answer have been had she worked the problem correctly?

15

34

43

51

138

Her computation was

\dfrac{x-9}{3}=43

Solve for

x,

then evaluate

\dfrac{x-3}{9}

Let

x

be the number. Cindy computed

\dfrac{x-9}{3} = 43,

x - 9 = 129

and

x = 138.

The correct computation gives

\dfrac{138-3}{9} = \dfrac{135}{9} = 15.

Thus, the correct answer is A.

Problem 2 in other years