"The number of 20-cent coins is four times as many as the number of 50-cent coins. "
let 1u be number of 50 cent coins
number of 50¢ → 1u number of 20¢ → 4 x 1u = 4u
" The value of the 20-cent coins is $11.40 more than the value of the 50-cent coins."
value of 50¢ (units) → 1u x 50 = 50u
value of 20¢ (units) → 4u x 20 = 80u
difference (units) → 80u - 50u = 30u
difference → $11.40 = 1140¢
30u → 1140 1u → 1140 ÷ 30 = 38
total value → 50u + 80u = 130u
130u → 130 x 38 = 4940 ¢ = $49.40