There are a total of 240 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Luis'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 Luis's tin can?
(a)
Number of 5-cent coins
=
25 x 240
= 96
Number of 10-cent coins and 20-cent coins
= 240 - 96
= 144
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 = 144
1 u = 144 ÷ 4 = 36
Number of 20-cent coins
= 3 u
= 3 x 36
= 108
(b)
100¢ = $1
Total value of the 20-cent coins in Luis's tin can
= 108 x 20
= 2160¢
= $21.60
Answer(s): (a) 108; (b) $21.60