There are a total of 390 pieces of 5-cent coins, 10-cent coins and 50-cent coins in Elijah's piggy bank.
45 of these coins are 5-cent coins. The number of 50-cent coins is five times the number of 10-cent coins.
- How many 50-cent coins are there?
- What is the total value of the 50-cent coins in Elijah's piggy bank?
(a)
Number of 5-cent coins
=
45 x 390
= 312
Number of 10-cent coins and 50-cent coins
= 390 - 312
= 78
Number of 10-cent coins = 1 u
Number of 50-cent coins = 5 u
Number of 10-cent coins
= 1 u + 5 u
= 6 u
6 u = 78
1 u = 78 ÷ 6 = 13
Number of 50-cent coins
= 5 u
= 5 x 13
= 65
(b)
100¢ = $1
Total value of the 50-cent coins in Elijah's piggy bank
= 65 x 50
= 3250¢
= $32.50
Answer(s): (a) 65; (b) $32.50