There are a total of 220 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Ben's coin box.
25 of these coins are 5-cent coins. The number of 20-cent coins is twice the number of 10-cent coins.
- How many 20-cent coins are there?
- What is the total value of the 20-cent coins in Ben's coin box?
(a)
Number of 5-cent coins
=
25 x 220
= 88
Number of 10-cent coins and 20-cent coins
= 220 - 88
= 132
Number of 10-cent coins = 1 u
Number of 20-cent coins = 2 u
Number of 10-cent coins
= 1 u + 2 u
= 3 u
3 u = 132
1 u = 132 ÷ 3 = 44
Number of 20-cent coins
= 2 u
= 2 x 44
= 88
(b)
100¢ = $1
Total value of the 20-cent coins in Ben's coin box
= 88 x 20
= 1760¢
= $17.60
Answer(s): (a) 88; (b) $17.60