PSLE
Billy and Owen have the same total number of coins. Billy has a number of twenty-cent coins and 46 five-cent coins. The total mass of his coins is 0.897 kg. Owen has a number of twenty-cent coins and 86 five-cent coins.

1. Who has more money in coins? How much more? Give your answers in this format. (Eg Adam, $12)
2. Each twenty-cent coin is 2.9 g heavier than each five-cent coin. What is the total mass of Owen's coins in kg?

(a)
Since Billy has less five-cent coins than Owen but both had the same number of coins, Billy had more money.

Both boys have the same number of coins. Since Billy has less five-cent coins than Owen, it means that Billy has more twenty-cent coins than Owen. So Billy has more money.

Difference in the number of five-cent coins.
= 86 - 46
= 40

Difference in the value of 1 five-cent coin and 1 twenty-cent coin
= 20 - 5
= 15¢

Amount that Billy had more than Owen
= 40 x 15
= 600¢
= $6

(b)
Difference in the mass between 40 five-cent coins and 40 twenty-cent coins
= 40 x 2.9
= 116 g
= 0.116 kg

Total mass of Owen's coins
= 0.897 - 0.116
= 0.781 kg

Answer(s): (a) Billy, $6; (b) 0.781 kg