Number of dimes: x Number of quarters: x + 3 Answer: B ) 0.10 x + 0.25 ( x + 3 ) = $1.80 Also we can solve this equation: 0.10 x + 0.25 x + 0.75 = 1.80 0.35 x = 1.80 - 0.75 0.35 x = 1.05 x = 1.05 : 0.35 x = 3, x + 3 = 6 He has 6 quarters and 3 dimes. ( 6 * 0.25 + 3 * 0.10 = 1.50 + 0.30 = $1.80 - correct)