PSLE
Tom and Reggie have the same total number of coins. Tom has a number of fifty-cent coins and 64 twenty-cent coins. The total mass of his coins is 0.662 kg. Reggie has a number of fifty-cent coins and 124 twenty-cent coins.

1. Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
2. Each fifty-cent coin is 1.6 g heavier than each twenty-cent coin. What is the total mass of Reggie's coins in kg?

(a)
Both boys have the same number of coins. Since Reggie has more twenty-cent coins than Tom, it means that Reggie has less fifty-cent coins than Tom.  So Reggie has less money.

Difference in the number of twenty-cent coins.
= 124 - 64
= 60

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

Amount that Reggie had less than Tom
= 60 x 30
= 1800¢
= $18

(b)
Difference in the mass between 60 twenty-cent coins and 60 fifty-cent coins
= 60 x 1.6
= 96 g
= 0.096 kg

Total mass of Reggie's coins
= 0.662 - 0.096
= 0.566 kg

Answer(s): (a) Tom, $18; (b) 0.566 kg