There are a total of 270 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Brandon's tin can.
35 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 Brandon's tin can?
(a)
Number of 5-cent coins
=
35 x 270
= 162
Number of 10-cent coins and 20-cent coins
= 270 - 162
= 108
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 = 108
1 u = 108 ÷ 4 = 27
Number of 20-cent coins
= 3 u
= 3 x 27
= 81
(b)
100¢ = $1
Total value of the 20-cent coins in Brandon's tin can
= 81 x 20
= 1620¢
= $16.20
Answer(s): (a) 81; (b) $16.20