1964 AMC 12 Problem 5

Attempt Problem 5 of the 1964 AMC 12 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 1964 AMC 12 solutions, or check the answer key.

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

y

varies directly as

x,

and if

y=8

when

x=4,

the value of

y

when

x=-8

is:

-16

-4

-2

4k,

k=\pm1,

\pm2,

\ldots

16k,

k=\pm1,

\pm2,

\ldots

Write direct variation as

y=kx

Use the first pair to find

k

Direct variation gives

y=kx.

From

8=4k,

k=2.

Therefore, when

x=-8,

y=2(-8)=-16.

Thus, the correct answer is A.

Problem 5 in other years