PSLE
Luis and Owen have the same total number of coins. Luis has a number of fifty-cent coins and 38 ten-cent coins. The total mass of his coins is 0.671 kg. Owen has a number of fifty-cent coins and 78 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 1.1 g heavier than each ten-cent coin. What is the total mass of Owen's coins in kg?

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

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

Difference in the number of ten-cent coins.
= 78 - 38
= 40

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

Amount that Luis had more than Owen
= 40 x 40
= 1600¢
= $16

(b)
Difference in the mass between 40 ten-cent coins and 40 fifty-cent coins
= 40 x 1.1
= 44 g
= 0.044 kg

Total mass of Owen's coins
= 0.671 - 0.044
= 0.627 kg

Answer(s): (a) Luis, $16; (b) 0.627 kg