PSLE Riordan and Cody have the same total number of coins. Riordan has a number of fifty-cent coins and 59 twenty-cent coins. The total mass of his coins is 1.18 kg. Cody has a number of fifty-cent coins and 79 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 3.1 g heavier than each twenty-cent coin. What is the total mass of Cody's coins in kg?
(a)
Since Riordan has less twenty-cent coins than Cody but both had the same number of coins, Riordan had more money.
Both boys have the same number of coins. Since Riordan has less twenty-cent coins than Cody, it means that Riordan has more fifty-cent coins than Cody. So Riordan has more money.
Difference in the number of twenty-cent coins.
= 79 - 59
= 20
Difference in the value of 1 twenty-cent coin and 1 fifty-cent coin
= 50 - 20
= 30¢
Amount that Riordan had more than Cody
= 20 x 30
= 600¢
= $6
(b)
Difference in the mass between 20 twenty-cent coins and 20 fifty-cent coins
= 20 x 3.1
= 62 g
= 0.062 kg
Total mass of Cody's coins
= 1.18 - 0.062
= 1.118 kg
Answer(s): (a) Riordan, $6; (b) 1.118 kg