PSLE Ken and Harry have the same total number of coins. Ken has a number of fifty-cent coins and 64 five-cent coins. The total mass of his coins is 1.026 kg. Harry has a number of fifty-cent coins and 84 five-cent coins.
- Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
- Each fifty-cent coin is 3.2 g heavier than each five-cent coin. What is the total mass of Harry's coins in kg?
(a)
Both boys have the same number of coins. Since Harry has more five-cent coins than Ken, it means that Harry has less fifty-cent coins than Ken. So Harry has less money.
Difference in the number of five-cent coins.
= 84 - 64
= 20
Difference in the value of 1 five-cent coin and 1 fifty-cent coin
= 50 - 5
= 45¢
Amount that Harry had less than Ken
= 20 x 45
= 900¢
= $9
(b)
Difference in the mass between 20 five-cent coins and 20 fifty-cent coins
= 20 x 3.2
= 64 g
= 0.064 kg
Total mass of Harry's coins
= 1.026 - 0.064
= 0.962 kg
Answer(s): (a) Ken, $9; (b) 0.962 kg