PSLE
Jeremy and Henry have the same total number of coins. Jeremy has a number of twenty-cent coins and 30 ten-cent coins. The total mass of his coins is 1.088 kg. Henry 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 2.9 g heavier than each ten-cent coin. What is the total mass of Henry's coins in kg?

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

Both boys have the same number of coins. Since Jeremy has less ten-cent coins than Henry, it means that Jeremy has more twenty-cent coins than Henry. So Jeremy 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 Jeremy had more than Henry
= 50 x 10
= 500¢
= $5

(b)
Difference in the mass between 50 ten-cent coins and 50 twenty-cent coins
= 50 x 2.9
= 145 g
= 0.145 kg

Total mass of Henry's coins
= 1.088 - 0.145
= 0.943 kg

Answer(s): (a) Jeremy, $5; (b) 0.943 kg