PSLE Sam and Perry have the same total number of coins. Sam has a number of ten-cent coins and 47 five-cent coins. The total mass of his coins is 0.833 kg. Perry has a number of ten-cent coins and 107 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 3.5 g heavier than each five-cent coin. What is the total mass of Perry's coins in kg?
(a)
Since Sam has less five-cent coins than Perry but both had the same number of coins, Sam had more money.
Both boys have the same number of coins. Since Sam has less five-cent coins than Perry, it means that Sam has more ten-cent coins than Perry. So Sam has more money.
Difference in the number of five-cent coins.
= 107 - 47
= 60
Difference in the value of 1 five-cent coin and 1 ten-cent coin
= 10 - 5
= 5¢
Amount that Sam had more than Perry
= 60 x 5
= 300¢
= $3
(b)
Difference in the mass between 60 five-cent coins and 60 ten-cent coins
= 60 x 3.5
= 210 g
= 0.21 kg
Total mass of Perry's coins
= 0.833 - 0.21
= 0.623 kg
Answer(s): (a) Sam, $3; (b) 0.623 kg