PSLE Cody and Ken have the same total number of coins. Cody has a number of twenty-cent coins and 58 ten-cent coins. The total mass of his coins is 0.741 kg. Ken has a number of twenty-cent coins and 108 ten-cent coins.
- Who has more money in coins? How much more? Give your answers in this format. (Eg Adam, $12)
- Each twenty-cent coin is 3.9 g heavier than each ten-cent coin. What is the total mass of Ken's coins in kg?
(a)
Since Cody has less ten-cent coins than Ken but both had the same number of coins, Cody had more money.
Both boys have the same number of coins. Since Cody has less ten-cent coins than Ken, it means that Cody has more twenty-cent coins than Ken. So Cody has more money.
Difference in the number of ten-cent coins.
= 108 - 58
= 50
Difference in the value of 1 ten-cent coin and 1 twenty-cent coin
= 20 - 10
= 10¢
Amount that Cody had more than Ken
= 50 x 10
= 500¢
= $5
(b)
Difference in the mass between 50 ten-cent coins and 50 twenty-cent coins
= 50 x 3.9
= 195 g
= 0.195 kg
Total mass of Ken's coins
= 0.741 - 0.195
= 0.546 kg
Answer(s): (a) Cody, $5; (b) 0.546 kg