PSLE
John and Asher have the same total number of coins. John has a number of twenty-cent coins and 45 ten-cent coins. The total mass of his coins is 0.663 kg. Asher has a number of twenty-cent coins and 75 ten-cent coins.

1. Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
2. Each twenty-cent coin is 2.6 g heavier than each ten-cent coin. What is the total mass of Asher's coins in kg?

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

Difference in the number of ten-cent coins.
= 75 - 45
= 30

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

Amount that Asher had less than John
= 30 x 10
= 300¢
= $3

(b)
Difference in the mass between 30 ten-cent coins and 30 twenty-cent coins
= 30 x 2.6
= 78 g
= 0.078 kg

Total mass of Asher's coins
= 0.663 - 0.078
= 0.585 kg

Answer(s): (a) John, $3; (b) 0.585 kg