PSLE
Julian and Ivan have the same total number of coins. Julian has a number of ten-cent coins and 30 five-cent coins. The total mass of his coins is 1.277 kg. Ivan has a number of ten-cent coins and 50 five-cent coins.

1. Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
2. Each ten-cent coin is 3.3 g heavier than each five-cent coin. What is the total mass of Ivan's coins in kg?

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

Difference in the number of five-cent coins.
= 50 - 30
= 20

Difference in the value of 1 five-cent coin and 1 ten-cent coin
= 10 - 5
= 5¢

Amount that Ivan had less than Julian
= 20 x 5
= 100¢
= $1

(b)
Difference in the mass between 20 five-cent coins and 20 ten-cent coins
= 20 x 3.3
= 66 g
= 0.066 kg

Total mass of Ivan's coins
= 1.277 - 0.066
= 1.211 kg

Answer(s): (a) Julian, $1; (b) 1.211 kg