PSLE Xavier and Ethan have the same total number of coins. Xavier has a number of twenty-cent coins and 63 five-cent coins. The total mass of his coins is 1.24 kg. Ethan has a number of twenty-cent coins and 103 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 Ethan's coins in kg?
(a)
Both boys have the same number of coins. Since Ethan has more five-cent coins than Xavier, it means that Ethan has less twenty-cent coins than Xavier. So Ethan has less money.
Difference in the number of five-cent coins.
= 103 - 63
= 40
Difference in the value of 1 five-cent coin and 1 twenty-cent coin
= 20 - 5
= 15¢
Amount that Ethan had less than Xavier
= 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 Ethan's coins
= 1.24 - 0.048
= 1.192 kg
Answer(s): (a) Xavier, $6; (b) 1.192 kg