PSLE
Ethan and Ken have the same total number of coins. Ethan has a number of fifty-cent coins and 60 five-cent coins. The total mass of his coins is 1.353 kg. Ken has a number of fifty-cent coins and 120 five-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 3.3 g heavier than each five-cent coin. What is the total mass of Ken's coins in kg?

(a)
Both boys have the same number of coins. Since Ken has more five-cent coins than Ethan, it means that Ken has less fifty-cent coins than Ethan.  So Ken has less money.

Difference in the number of five-cent coins.
= 120 - 60
= 60

Difference in the value of 1 five-cent coin and 1 fifty-cent coin
= 50 - 5
= 45¢

Amount that Ken had less than Ethan
= 60 x 45
= 2700¢
= $27

(b)
Difference in the mass between 60 five-cent coins and 60 fifty-cent coins
= 60 x 3.3
= 198 g
= 0.198 kg

Total mass of Ken's coins
= 1.353 - 0.198
= 1.155 kg

Answer(s): (a) Ethan, $27; (b) 1.155 kg