PSLE
Reggie and Jeremy have the same total number of coins. Reggie has a number of fifty-cent coins and 66 twenty-cent coins. The total mass of his coins is 0.352 kg. Jeremy has a number of fifty-cent coins and 116 twenty-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 2.8 g heavier than each twenty-cent coin. What is the total mass of Jeremy's coins in kg?

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

Difference in the number of twenty-cent coins.
= 116 - 66
= 50

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

Amount that Jeremy had less than Reggie
= 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 Jeremy's coins
= 0.352 - 0.14
= 0.212 kg

Answer(s): (a) Reggie, $15; (b) 0.212 kg