There are a total of 100 pieces of 5-cent coins, 20-cent coins and 50-cent coins in Howard's piggy bank.
45 of these coins are 5-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 Howard's piggy bank?
(a)
Number of 5-cent coins
=
45 x 100
= 80
Number of 20-cent coins and 50-cent coins
= 100 - 80
= 20
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 = 20
1 u = 20 ÷ 4 = 5
Number of 50-cent coins
= 3 u
= 3 x 5
= 15
(b)
100¢ = $1
Total value of the 50-cent coins in Howard's piggy bank
= 15 x 50
= 750¢
= $7.50
Answer(s): (a) 15; (b) $7.50