PSLE Ken and Brandon have the same total number of coins. Ken has a number of ten-cent coins and 40 five-cent coins. The total mass of his coins is 1.27 kg. Brandon has a number of ten-cent coins and 100 five-cent coins.
- Who has more money in coins? How much more? Give your answers in this format. (Eg Adam, $12)
- Each ten-cent coin is 3.2 g heavier than each five-cent coin. What is the total mass of Brandon's coins in kg?
(a)
Since Ken has less five-cent coins than Brandon but both had the same number of coins, Ken had more money.
Both boys have the same number of coins. Since Ken has less five-cent coins than Brandon, it means that Ken has more ten-cent coins than Brandon. So Ken has more money.
Difference in the number of five-cent coins.
= 100 - 40
= 60
Difference in the value of 1 five-cent coin and 1 ten-cent coin
= 10 - 5
= 5¢
Amount that Ken had more than Brandon
= 60 x 5
= 300¢
= $3
(b)
Difference in the mass between 60 five-cent coins and 60 ten-cent coins
= 60 x 3.2
= 192 g
= 0.192 kg
Total mass of Brandon's coins
= 1.27 - 0.192
= 1.078 kg
Answer(s): (a) Ken, $3; (b) 1.078 kg