There are a total of 120 pieces of 5-cent coins, 20-cent coins and 50-cent coins in Riordan's piggy bank.
34 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 Riordan's piggy bank?
(a)
Number of 5-cent coins
=
34 x 120
= 90
Number of 20-cent coins and 50-cent coins
= 120 - 90
= 30
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 = 30
1 u = 30 ÷ 6 = 5
Number of 50-cent coins
= 5 u
= 5 x 5
= 25
(b)
100¢ = $1
Total value of the 50-cent coins in Riordan's piggy bank
= 25 x 50
= 1250¢
= $12.50
Answer(s): (a) 25; (b) $12.50