PSLE
Harry and Nick have the same total number of coins. Harry has a number of twenty-cent coins and 60 ten-cent coins. The total mass of his coins is 0.48 kg. Nick has a number of twenty-cent coins and 90 ten-cent coins.

1. Who has more money in coins? How much more? Give your answers in this format. (Eg Adam, $12)
2. Each twenty-cent coin is 2.4 g heavier than each ten-cent coin. What is the total mass of Nick's coins in kg?

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

Both boys have the same number of coins. Since Harry has less ten-cent coins than Nick, it means that Harry has more twenty-cent coins than Nick. So Harry has more money.

Difference in the number of ten-cent coins.
= 90 - 60
= 30

Difference in the value of 1 ten-cent coin and 1 twenty-cent coin
= 20 - 10
= 10¢

Amount that Harry had more than Nick
= 30 x 10
= 300¢
= $3

(b)
Difference in the mass between 30 ten-cent coins and 30 twenty-cent coins
= 30 x 2.4
= 72 g
= 0.072 kg

Total mass of Nick's coins
= 0.48 - 0.072
= 0.408 kg

Answer(s): (a) Harry, $3; (b) 0.408 kg