PSLE
Flynn and Peter have the same total number of coins. Flynn has a number of twenty-cent coins and 56 ten-cent coins. The total mass of his coins is 0.597 kg. Peter has a number of twenty-cent coins and 76 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 3.9 g heavier than each ten-cent coin. What is the total mass of Peter's coins in kg?

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

Difference in the number of ten-cent coins.
= 76 - 56
= 20

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

Amount that Peter had less than Flynn
= 20 x 10
= 200¢
= $2

(b)
Difference in the mass between 20 ten-cent coins and 20 twenty-cent coins
= 20 x 3.9
= 78 g
= 0.078 kg

Total mass of Peter's coins
= 0.597 - 0.078
= 0.519 kg

Answer(s): (a) Flynn, $2; (b) 0.519 kg