PSLE
Liam and Ahmad have the same total number of coins. Liam has a number of fifty-cent coins and 47 ten-cent coins. The total mass of his coins is 1.391 kg. Ahmad has a number of fifty-cent coins and 87 ten-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 3.8 g heavier than each ten-cent coin. What is the total mass of Ahmad's coins in kg?

(a)
Since Liam has less ten-cent coins than Ahmad but both had the same number of coins, Liam had more money.

Both boys have the same number of coins. Since Liam has less ten-cent coins than Ahmad, it means that Liam has more fifty-cent coins than Ahmad. So Liam has more money.

Difference in the number of ten-cent coins.
= 87 - 47
= 40

Difference in the value of 1 ten-cent coin and 1 fifty-cent coin
= 50 - 10
= 40¢

Amount that Liam had more than Ahmad
= 40 x 40
= 1600¢
= $16

(b)
Difference in the mass between 40 ten-cent coins and 40 fifty-cent coins
= 40 x 3.8
= 152 g
= 0.152 kg

Total mass of Ahmad's coins
= 1.391 - 0.152
= 1.239 kg

Answer(s): (a) Liam, $16; (b) 1.239 kg