There are a total of 180 pieces of 5-cent coins, 10-cent coins and 50-cent coins in Simon's coin box.
23 of these coins are 5-cent coins. The number of 50-cent coins is thrice the number of 10-cent coins.
- How many 50-cent coins are there?
- What is the total value of the 50-cent coins in Simon's coin box?
(a)
Number of 5-cent coins
=
23 x 180
= 120
Number of 10-cent coins and 50-cent coins
= 180 - 120
= 60
Number of 10-cent coins = 1 u
Number of 50-cent coins = 3 u
Number of 10-cent coins
= 1 u + 3 u
= 4 u
4 u = 60
1 u = 60 ÷ 4 = 15
Number of 50-cent coins
= 3 u
= 3 x 15
= 45
(b)
100¢ = $1
Total value of the 50-cent coins in Simon's coin box
= 45 x 50
= 2250¢
= $22.50
Answer(s): (a) 45; (b) $22.50