Robert purchased $2000 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 option.
A) 20 B) 27 C) 30 D) 60 E) 70
I started off with looking at the answer choices... 20-27-30 are in a tight range, so my guess was to look and rule out the bigger numbers.   The total amount is $3000. So with 70 bonds, each $50 = $3500 , we already exceed the $3000 limit. Hence 70 is the answer.
<result>E</result>
Robert purchased $2000 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?