PSLE
Zane and Michael have the same total number of coins. Zane has a number of fifty-cent coins and 45 ten-cent coins. The total mass of his coins is 0.415 kg. Michael has a number of fifty-cent coins and 75 ten-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 1.8 g heavier than each ten-cent coin. What is the total mass of Michael's coins in kg?

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

Both boys have the same number of coins. Since Zane has less ten-cent coins than Michael, it means that Zane has more fifty-cent coins than Michael. So Zane has more money.

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

Difference in the value of 1 ten-cent coin and 1 fifty-cent coin
= 50 - 10
= 40¢

Amount that Zane had more than Michael
= 30 x 40
= 1200¢
= $12

(b)
Difference in the mass between 30 ten-cent coins and 30 fifty-cent coins
= 30 x 1.8
= 54 g
= 0.054 kg

Total mass of Michael's coins
= 0.415 - 0.054
= 0.361 kg

Answer(s): (a) Zane, $12; (b) 0.361 kg