PSLE
Caden and Oliver have the same total number of coins. Caden has a number of fifty-cent coins and 53 twenty-cent coins. The total mass of his coins is 0.934 kg. Oliver has a number of fifty-cent coins and 103 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 2.8 g heavier than each twenty-cent coin. What is the total mass of Oliver's coins in kg?

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

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

Difference in the number of twenty-cent coins.
= 103 - 53
= 50

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

Amount that Caden had more than Oliver
= 50 x 30
= 1500¢
= $15

(b)
Difference in the mass between 50 twenty-cent coins and 50 fifty-cent coins
= 50 x 2.8
= 140 g
= 0.14 kg

Total mass of Oliver's coins
= 0.934 - 0.14
= 0.794 kg

Answer(s): (a) Caden, $15; (b) 0.794 kg