The table below shows the distance s in feet a ball rolls down an inclined plane in t seconds. t 0 1 2 3 4 5 s 0 10 40 90 160 250 The distance s for t=2.5 is:

1957 AMC 12 Problem 15

Attempt Problem 15 of the 1957 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 1957 AMC 12 solutions, or check the answer key.

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

15.

The table below shows the distance

s

in feet a ball rolls down an inclined plane in

t

seconds.

$t$	$0$	$1$	$2$	$3$	$4$	$5$
$s$	$0$	$10$	$40$	$90$	$160$	$250$

The distance

s

for

t=2.5

is:

45

62.5

70

75

82.5

Compare each listed

s

-value with the square of its

t

-value

The table follows

s=10t^2

The entries follow

s=10t^2.

Thus, at

t=2.5,

s=10(2.5)^2=10(6.25)=62.5.

Therefore, the correct answer is B.