PSLE
Sam and Sean have the same total number of coins. Sam has a number of fifty-cent coins and 46 five-cent coins. The total mass of his coins is 0.285 kg. Sean has a number of fifty-cent coins and 86 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 1.5 g heavier than each five-cent coin. What is the total mass of Sean's coins in kg?

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

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

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

Amount that Sean had less than Sam
= 40 x 45
= 1800¢
= $18

(b)
Difference in the mass between 40 five-cent coins and 40 fifty-cent coins
= 40 x 1.5
= 60 g
= 0.06 kg

Total mass of Sean's coins
= 0.285 - 0.06
= 0.225 kg

Answer(s): (a) Sam, $18; (b) 0.225 kg