Half the people on a bus get off at each stop after the first, and no one gets on after the first stop. If only one person gets off at stop number 9, how many people got on at the first stop?  Pick one:
A) 128 B) 64 C) 32 D) 16 E) 256
7 - &gt; 1   6 - &gt; 2   5 - &gt; 4   4 - &gt; 8   3 - &gt; 16   2 - &gt; 32   1 - &gt; 64   because people get off after the first stop   =&gt; the formula will be : 2^(n-1) where n is the stop number   in this case n = 9   =&gt; 2^(9-1) = 2^8 = 256   =&gt; answer is 256
<result>E</result>
Half the people on a bus get off at each stop after the first, and no one gets on after the first stop. If only one person gets off at stop number 9, how many people got on at the first stop?