PSLE Oscar and Jenson have the same total number of coins. Oscar has a number of fifty-cent coins and 58 twenty-cent coins. The total mass of his coins is 0.728 kg. Jenson has a number of fifty-cent coins and 78 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 1.6 g heavier than each twenty-cent coin. What is the total mass of Jenson's coins in kg?
(a)
Since Oscar has less twenty-cent coins than Jenson 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 Jenson, it means that Oscar has more fifty-cent coins than Jenson. So Oscar has more money.
Difference in the number of twenty-cent coins.
= 78 - 58
= 20
Difference in the value of 1 twenty-cent coin and 1 fifty-cent coin
= 50 - 20
= 30¢
Amount that Oscar had more than Jenson
= 20 x 30
= 600¢
= $6
(b)
Difference in the mass between 20 twenty-cent coins and 20 fifty-cent coins
= 20 x 1.6
= 32 g
= 0.032 kg
Total mass of Jenson's coins
= 0.728 - 0.032
= 0.696 kg
Answer(s): (a) Oscar, $6; (b) 0.696 kg