There are a total of 280 pieces of 10-cent coins, 20-cent coins and 50-cent coins in Cole's coin box.
310 of these coins are 10-cent coins. The number of 50-cent coins is thrice the number of 20-cent coins.
- How many 50-cent coins are there?
- What is the total value of the 50-cent coins in Cole's coin box?
(a)
Number of 10-cent coins
=
310 x 280
= 84
Number of 20-cent coins and 50-cent coins
= 280 - 84
= 196
Number of 20-cent coins = 1 u
Number of 50-cent coins = 3 u
Number of 20-cent coins
= 1 u + 3 u
= 4 u
4 u = 196
1 u = 196 ÷ 4 = 49
Number of 50-cent coins
= 3 u
= 3 x 49
= 147
(b)
100¢ = $1
Total value of the 50-cent coins in Cole's coin box
= 147 x 50
= 7350¢
= $73.50
Answer(s): (a) 147; (b) $73.50