1955 AMC 12 Problem 1

Attempt Problem 1 of the 1955 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 1955 AMC 12 solutions, or check the answer key.

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

Which one of the following is not equivalent to

0.000000375?

3.75\times10^{-7}

3\dfrac34\times10^{-7}

375\times10^{-9}

\dfrac38\times10^{-7}

\dfrac{3}{8000000}

Rewrite every choice with the same power of

10

The decimal is

3.75\times10^{-7}

The given decimal is

3.75\times10^{-7}.

Choices A and B state this directly, while

375\times10^{-9}=3.75\times10^{-7}

and

\frac38\times10^{-6}

=0.375\times10^{-6}

=3.75\times10^{-7}.

But

\frac38\times10^{-7}=3.75\times10^{-8},

which is ten times smaller.

Thus, the correct answer is D.

Problem 1 in other years