There are a total of 170 pieces of 5-cent coins, 20-cent coins and 50-cent coins in Fred's coin box.
25 of these coins are 5-cent coins. The number of 50-cent coins is five times the number of 20-cent coins.
- How many 50-cent coins are there?
- What is the total value of the 50-cent coins in Fred's coin box?
(a)
Number of 5-cent coins
=
25 x 170
= 68
Number of 20-cent coins and 50-cent coins
= 170 - 68
= 102
Number of 20-cent coins = 1 u
Number of 50-cent coins = 5 u
Number of 20-cent coins
= 1 u + 5 u
= 6 u
6 u = 102
1 u = 102 ÷ 6 = 17
Number of 50-cent coins
= 5 u
= 5 x 17
= 85
(b)
100¢ = $1
Total value of the 50-cent coins in Fred's coin box
= 85 x 50
= 4250¢
= $42.50
Answer(s): (a) 85; (b) $42.50