Question

Robert purchased $2,000 worth of U.S. savings bonds. If bonds are sold in $50 or $100 denominations only, which of the following CANNOT be the number of U.S. savings bonds that Robert purchased?

A.)29
B.)27
C.)30
D.)40
E.)50

Answer 1

let's say a = no. for 50$ bonds and b = no. for 100$ bonds

50a+100b=2000 => a+2b=40

then you have:
a) a+b = 29 => b=11, a = 18
do the same for b, c, d, e

The number of bonds cannot be 50
a+b=50
a+2b=40 => b=-10, a=60 ( b it's a negative number)

Answer 2

so the answers B