Robert purchased $4000 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 correct choice: A) 20 B) 47 C) 50 D) 80 E) 90
I started off with looking at the answer choices... 20-47-50 are in a tight range, so my guess was to look and rule out the bigger numbers.   The total amount is $4000. So with 90 bonds, each $50 = $4500 , we already exceed the $4000 limit. Hence E is the answer.   90 remains.
<result>E</result>
Robert purchased $4000 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?