PSLE
Henry and Zeph have the same total number of coins. Henry has a number of fifty-cent coins and 50 ten-cent coins. The total mass of his coins is 0.505 kg. Zeph has a number of fifty-cent coins and 110 ten-cent coins.

1. Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
2. Each fifty-cent coin is 2.5 g heavier than each ten-cent coin. What is the total mass of Zeph's coins in kg?

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

Difference in the number of ten-cent coins.
= 110 - 50
= 60

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

Amount that Zeph had less than Henry
= 60 x 40
= 2400¢
= $24

(b)
Difference in the mass between 60 ten-cent coins and 60 fifty-cent coins
= 60 x 2.5
= 150 g
= 0.15 kg

Total mass of Zeph's coins
= 0.505 - 0.15
= 0.355 kg

Answer(s): (a) Henry, $24; (b) 0.355 kg