There are a total of 360 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Ethan's piggy bank.
35 of these coins are 5-cent coins. The number of 20-cent coins is twice the number of 10-cent coins.
- How many 20-cent coins are there?
- What is the total value of the 20-cent coins in Ethan's piggy bank?
(a)
Number of 5-cent coins
=
35 x 360
= 216
Number of 10-cent coins and 20-cent coins
= 360 - 216
= 144
Number of 10-cent coins = 1 u
Number of 20-cent coins = 2 u
Number of 10-cent coins
= 1 u + 2 u
= 3 u
3 u = 144
1 u = 144 ÷ 3 = 48
Number of 20-cent coins
= 2 u
= 2 x 48
= 96
(b)
100¢ = $1
Total value of the 20-cent coins in Ethan's piggy bank
= 96 x 20
= 1920¢
= $19.20
Answer(s): (a) 96; (b) $19.20