There are a total of 310 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Nick's glass jar.
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 Nick's glass jar?
(a)
Number of 5-cent coins
=
25 x 310
= 124
Number of 10-cent coins and 20-cent coins
= 310 - 124
= 186
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 = 186
1 u = 186 ÷ 3 = 62
Number of 20-cent coins
= 2 u
= 2 x 62
= 124
(b)
100¢ = $1
Total value of the 20-cent coins in Nick's glass jar
= 124 x 20
= 2480¢
= $24.80
Answer(s): (a) 124; (b) $24.80