PSLE Wesley and Sean have the same total number of coins. Wesley has a number of twenty-cent coins and 69 five-cent coins. The total mass of his coins is 0.966 kg. Sean has a number of twenty-cent coins and 109 five-cent coins.
- Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
- Each twenty-cent coin is 1.2 g heavier than each five-cent coin. What is the total mass of Sean's coins in kg?
(a)
Both boys have the same number of coins. Since Sean has more five-cent coins than Wesley, it means that Sean has less twenty-cent coins than Wesley. So Sean has less money.
Difference in the number of five-cent coins.
= 109 - 69
= 40
Difference in the value of 1 five-cent coin and 1 twenty-cent coin
= 20 - 5
= 15¢
Amount that Sean had less than Wesley
= 40 x 15
= 600¢
= $6
(b)
Difference in the mass between 40 five-cent coins and 40 twenty-cent coins
= 40 x 1.2
= 48 g
= 0.048 kg
Total mass of Sean's coins
= 0.966 - 0.048
= 0.918 kg
Answer(s): (a) Wesley, $6; (b) 0.918 kg