PSLE
Archie and Reggie have the same total number of coins. Archie has a number of fifty-cent coins and 30 twenty-cent coins. The total mass of his coins is 1.384 kg. Reggie has a number of fifty-cent coins and 60 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 3.7 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 Archie, it means that Reggie has less fifty-cent coins than Archie.  So Reggie has less money.

Difference in the number of twenty-cent coins.
= 60 - 30
= 30

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

Amount that Reggie had less than Archie
= 30 x 30
= 900¢
= $9

(b)
Difference in the mass between 30 twenty-cent coins and 30 fifty-cent coins
= 30 x 3.7
= 111 g
= 0.111 kg

Total mass of Reggie's coins
= 1.384 - 0.111
= 1.273 kg

Answer(s): (a) Archie, $9; (b) 1.273 kg