PSLE Oscar and Reggie have the same total number of coins. Oscar has a number of fifty-cent coins and 50 twenty-cent coins. The total mass of his coins is 0.269 kg. Reggie has a number of fifty-cent coins and 110 twenty-cent coins.
- Who has more money in coins? How much more? Give your answers in this format. (Eg Adam, $12)
- Each fifty-cent coin is 1.4 g heavier than each twenty-cent coin. What is the total mass of Reggie's coins in kg?
(a)
Since Oscar has less twenty-cent coins than Reggie but both had the same number of coins, Oscar had more money.
Both boys have the same number of coins. Since Oscar has less twenty-cent coins than Reggie, it means that Oscar has more fifty-cent coins than Reggie. So Oscar has more money.
Difference in the number of twenty-cent coins.
= 110 - 50
= 60
Difference in the value of 1 twenty-cent coin and 1 fifty-cent coin
= 50 - 20
= 30¢
Amount that Oscar had more than Reggie
= 60 x 30
= 1800¢
= $18
(b)
Difference in the mass between 60 twenty-cent coins and 60 fifty-cent coins
= 60 x 1.4
= 84 g
= 0.084 kg
Total mass of Reggie's coins
= 0.269 - 0.084
= 0.185 kg
Answer(s): (a) Oscar, $18; (b) 0.185 kg