PSLE Neave and Bobby have the same total number of coins. Neave has a number of fifty-cent coins and 68 ten-cent coins. The total mass of his coins is 0.794 kg. Bobby has a number of fifty-cent coins and 118 ten-cent coins.
- Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
- Each fifty-cent coin is 1.6 g heavier than each ten-cent coin. What is the total mass of Bobby's coins in kg?
(a)
Both boys have the same number of coins. Since Bobby has more ten-cent coins than Neave, it means that Bobby has less fifty-cent coins than Neave. So Bobby has less money.
Difference in the number of ten-cent coins.
= 118 - 68
= 50
Difference in the value of 1 ten-cent coin and 1 fifty-cent coin
= 50 - 10
= 40¢
Amount that Bobby had less than Neave
= 50 x 40
= 2000¢
= $20
(b)
Difference in the mass between 50 ten-cent coins and 50 fifty-cent coins
= 50 x 1.6
= 80 g
= 0.08 kg
Total mass of Bobby's coins
= 0.794 - 0.08
= 0.714 kg
Answer(s): (a) Neave, $20; (b) 0.714 kg