PSLE Tim and Jeremy have the same total number of coins. Tim has a number of twenty-cent coins and 50 ten-cent coins. The total mass of his coins is 0.491 kg. Jeremy has a number of twenty-cent coins and 110 ten-cent coins.
- Who has less money in coins? How much less? Give your answers in this format. (Eg Adam, $12)
- Each twenty-cent coin is 2.5 g heavier than each ten-cent coin. What is the total mass of Jeremy's coins in kg?
(a)
Both boys have the same number of coins. Since Jeremy has more ten-cent coins than Tim, it means that Jeremy has less twenty-cent coins than Tim. So Jeremy has less money.
Difference in the number of ten-cent coins.
= 110 - 50
= 60
Difference in the value of 1 ten-cent coin and 1 twenty-cent coin
= 20 - 10
= 10¢
Amount that Jeremy had less than Tim
= 60 x 10
= 600¢
= $6
(b)
Difference in the mass between 60 ten-cent coins and 60 twenty-cent coins
= 60 x 2.5
= 150 g
= 0.15 kg
Total mass of Jeremy's coins
= 0.491 - 0.15
= 0.341 kg
Answer(s): (a) Tim, $6; (b) 0.341 kg