PSLE
Flynn and Luis have the same total number of coins. Flynn has a number of fifty-cent coins and 56 twenty-cent coins. The total mass of his coins is 1.71 kg. Luis has a number of fifty-cent coins and 96 twenty-cent coins.

1. Who has more money in coins? How much more? Give your answers in this format. (Eg Adam, $12)
2. Each fifty-cent coin is 3.8 g heavier than each twenty-cent coin. What is the total mass of Luis's coins in kg?

(a)
Since Flynn has less twenty-cent coins than Luis but both had the same number of coins, Flynn had more money.

Both boys have the same number of coins. Since Flynn has less twenty-cent coins than Luis, it means that Flynn has more fifty-cent coins than Luis. So Flynn has more money.

Difference in the number of twenty-cent coins.
= 96 - 56
= 40

Difference in the value of 1 twenty-cent coin and 1 fifty-cent coin
= 50 - 20
= 30¢

Amount that Flynn had more than Luis
= 40 x 30
= 1200¢
= $12

(b)
Difference in the mass between 40 twenty-cent coins and 40 fifty-cent coins
= 40 x 3.8
= 152 g
= 0.152 kg

Total mass of Luis's coins
= 1.71 - 0.152
= 1.558 kg

Answer(s): (a) Flynn, $12; (b) 1.558 kg