PSLE Wesley and Billy have the same total number of coins. Wesley has a number of twenty-cent coins and 50 ten-cent coins. The total mass of his coins is 0.399 kg. Billy has a number of twenty-cent coins and 70 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 2.1 g heavier than each ten-cent coin. What is the total mass of Billy's coins in kg?
(a)
Since Wesley has less ten-cent coins than Billy but both had the same number of coins, Wesley had more money.
Both boys have the same number of coins. Since Wesley has less ten-cent coins than Billy, it means that Wesley has more twenty-cent coins than Billy. So Wesley has more money.
Difference in the number of ten-cent coins.
= 70 - 50
= 20
Difference in the value of 1 ten-cent coin and 1 twenty-cent coin
= 20 - 10
= 10¢
Amount that Wesley had more than Billy
= 20 x 10
= 200¢
= $2
(b)
Difference in the mass between 20 ten-cent coins and 20 twenty-cent coins
= 20 x 2.1
= 42 g
= 0.042 kg
Total mass of Billy's coins
= 0.399 - 0.042
= 0.357 kg
Answer(s): (a) Wesley, $2; (b) 0.357 kg