There are a total of 260 pieces of 5-cent coins, 10-cent coins and 20-cent coins in Sam's glass jar.
45 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 Sam's glass jar?
(a)
Number of 5-cent coins
=
45 x 260
= 208
Number of 10-cent coins and 20-cent coins
= 260 - 208
= 52
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 = 52
1 u = 52 ÷ 4 = 13
Number of 20-cent coins
= 3 u
= 3 x 13
= 39
(b)
100¢ = $1
Total value of the 20-cent coins in Sam's glass jar
= 39 x 20
= 780¢
= $7.80
Answer(s): (a) 39; (b) $7.80