PSLE
Seth and Peter have the same total number of coins. Seth has a number of fifty-cent coins and 35 five-cent coins. The total mass of his coins is 0.516 kg. Peter has a number of fifty-cent coins and 75 five-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 2.7 g heavier than each five-cent coin. What is the total mass of Peter's coins in kg?

(a)
Since Seth has less five-cent coins than Peter but both had the same number of coins, Seth had more money.

Both boys have the same number of coins. Since Seth has less five-cent coins than Peter, it means that Seth has more fifty-cent coins than Peter. So Seth has more money.

Difference in the number of five-cent coins.
= 75 - 35
= 40

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

Amount that Seth had more than Peter
= 40 x 45
= 1800¢
= $18

(b)
Difference in the mass between 40 five-cent coins and 40 fifty-cent coins
= 40 x 2.7
= 108 g
= 0.108 kg

Total mass of Peter's coins
= 0.516 - 0.108
= 0.408 kg

Answer(s): (a) Seth, $18; (b) 0.408 kg