PSLE
Eric and Luke have the same total number of coins. Eric has a number of twenty-cent coins and 43 five-cent coins. The total mass of his coins is 1.202 kg. Luke has a number of twenty-cent coins and 63 five-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 3.6 g heavier than each five-cent coin. What is the total mass of Luke's coins in kg?

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

Difference in the number of five-cent coins.
= 63 - 43
= 20

Difference in the value of 1 five-cent coin and 1 twenty-cent coin
= 20 - 5
= 15¢

Amount that Luke had less than Eric
= 20 x 15
= 300¢
= $3

(b)
Difference in the mass between 20 five-cent coins and 20 twenty-cent coins
= 20 x 3.6
= 72 g
= 0.072 kg

Total mass of Luke's coins
= 1.202 - 0.072
= 1.13 kg

Answer(s): (a) Eric, $3; (b) 1.13 kg