There are a total of 360 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Sean's tin can.
25 of these coins are 5-cent coins. The number of 20-cent coins is thrice the number of 10-cent coins.
- How many 20-cent coins are there?
- What is the total value of the 20-cent coins in Sean's tin can?
(a)
Number of 5-cent coins
=
25 x 360
= 144
Number of 10-cent coins and 20-cent coins
= 360 - 144
= 216
Number of 10-cent coins = 1 u
Number of 20-cent coins = 3 u
Number of 10-cent coins
= 1 u + 3 u
= 4 u
4 u = 216
1 u = 216 ÷ 4 = 54
Number of 20-cent coins
= 3 u
= 3 x 54
= 162
(b)
100¢ = $1
Total value of the 20-cent coins in Sean's tin can
= 162 x 20
= 3240¢
= $32.40
Answer(s): (a) 162; (b) $32.40