PSLE
Warren and Ivan have the same total number of coins. Warren has a number of twenty-cent coins and 30 ten-cent coins. The total mass of his coins is 1.044 kg. Ivan has a number of twenty-cent coins and 80 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 3.7 g heavier than each ten-cent coin. What is the total mass of Ivan's coins in kg?

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

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

Difference in the number of ten-cent coins.
= 80 - 30
= 50

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

Amount that Warren had more than Ivan
= 50 x 10
= 500¢
= $5

(b)
Difference in the mass between 50 ten-cent coins and 50 twenty-cent coins
= 50 x 3.7
= 185 g
= 0.185 kg

Total mass of Ivan's coins
= 1.044 - 0.185
= 0.859 kg

Answer(s): (a) Warren, $5; (b) 0.859 kg