PSLE
Nick and Ivan have the same total number of coins. Nick has a number of twenty-cent coins and 60 ten-cent coins. The total mass of his coins is 1.355 kg. Ivan 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 3.9 g heavier than each ten-cent coin. What is the total mass of Ivan's coins in kg?

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

Both boys have the same number of coins. Since Nick has less ten-cent coins than Ivan, it means that Nick has more twenty-cent coins than Ivan. So Nick has more money.

Difference in the number of ten-cent coins.
= 80 - 60
= 20

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

Amount that Nick had more than Ivan
= 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 Ivan's coins
= 1.355 - 0.078
= 1.277 kg

Answer(s): (a) Nick, $2; (b) 1.277 kg