There are a total of 290 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Paul's piggy bank.
25 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 Paul's piggy bank?
(a)
Number of 5-cent coins
=
25 x 290
= 116
Number of 10-cent coins and 20-cent coins
= 290 - 116
= 174
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 = 174
1 u = 174 ÷ 3 = 58
Number of 20-cent coins
= 2 u
= 2 x 58
= 116
(b)
100¢ = $1
Total value of the 20-cent coins in Paul's piggy bank
= 116 x 20
= 2320¢
= $23.20
Answer(s): (a) 116; (b) $23.20