Q:Robert purchased $1000 worth of US saving bonds. If bonds are sold in $50 or $100 denominations only, which of the following CANNOT be the number of US saving bonds that Robert purchased? Choose the most appropriate option:
A) 10  B) 12  C) 17  D) 20  E) 30
I started off with looking at the answer choices... 10-12-17-20 are in a tight range, so my guess was to look and rule out the bigger numbers.   The total amount is $1000. So with 30 bonds, each $50 = $1500 , we already exceed the $1000 limit. Hence 30 is the answer.
<result>E</result>
Q:Robert purchased $1000 worth of US saving bonds. If bonds are sold in $50 or $100 denominations only, which of the following CANNOT be the number of US saving bonds that Robert purchased?