There are a total of 210 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Fabian's tin can.
47 of these coins are 5-cent coins. The number of 20-cent coins is four times the number of 10-cent coins.
- How many 20-cent coins are there?
- What is the total value of the 20-cent coins in Fabian's tin can?
(a)
Number of 5-cent coins
=
47 x 210
= 120
Number of 10-cent coins and 20-cent coins
= 210 - 120
= 90
Number of 10-cent coins = 1 u
Number of 20-cent coins = 4 u
Number of 10-cent coins
= 1 u + 4 u
= 5 u
5 u = 90
1 u = 90 ÷ 5 = 18
Number of 20-cent coins
= 4 u
= 4 x 18
= 72
(b)
100¢ = $1
Total value of the 20-cent coins in Fabian's tin can
= 72 x 20
= 1440¢
= $14.40
Answer(s): (a) 72; (b) $14.40