PSLE
Gabriel and Fabian have the same total number of coins. Gabriel has a number of fifty-cent coins and 55 twenty-cent coins. The total mass of his coins is 0.389 kg. Fabian has a number of fifty-cent coins and 85 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 2.2 g heavier than each twenty-cent coin. What is the total mass of Fabian's coins in kg?

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

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

Difference in the number of twenty-cent coins.
= 85 - 55
= 30

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

Amount that Gabriel had more than Fabian
= 30 x 30
= 900¢
= $9

(b)
Difference in the mass between 30 twenty-cent coins and 30 fifty-cent coins
= 30 x 2.2
= 66 g
= 0.066 kg

Total mass of Fabian's coins
= 0.389 - 0.066
= 0.323 kg

Answer(s): (a) Gabriel, $9; (b) 0.323 kg