PSLE Elijah and Mark have the same total number of coins. Elijah has a number of fifty-cent coins and 58 five-cent coins. The total mass of his coins is 0.684 kg. Mark has a number of fifty-cent coins and 98 five-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 2.3 g heavier than each five-cent coin. What is the total mass of Mark's coins in kg?
(a)
Since Elijah has less five-cent coins than Mark but both had the same number of coins, Elijah had more money.
Both boys have the same number of coins. Since Elijah has less five-cent coins than Mark, it means that Elijah has more fifty-cent coins than Mark. So Elijah has more money.
Difference in the number of five-cent coins.
= 98 - 58
= 40
Difference in the value of 1 five-cent coin and 1 fifty-cent coin
= 50 - 5
= 45¢
Amount that Elijah had more than Mark
= 40 x 45
= 1800¢
= $18
(b)
Difference in the mass between 40 five-cent coins and 40 fifty-cent coins
= 40 x 2.3
= 92 g
= 0.092 kg
Total mass of Mark's coins
= 0.684 - 0.092
= 0.592 kg
Answer(s): (a) Elijah, $18; (b) 0.592 kg