There are a total of 130 pieces of 10-cent coins, 20-cent coins and 50-cent coins in David's glass jar.
35 of these coins are 10-cent coins. The number of 50-cent coins is thrice the number of 20-cent coins.
- How many 50-cent coins are there?
- What is the total value of the 50-cent coins in David's glass jar?
(a)
Number of 10-cent coins
=
35 x 130
= 78
Number of 20-cent coins and 50-cent coins
= 130 - 78
= 52
Number of 20-cent coins = 1 u
Number of 50-cent coins = 3 u
Number of 20-cent coins
= 1 u + 3 u
= 4 u
4 u = 52
1 u = 52 ÷ 4 = 13
Number of 50-cent coins
= 3 u
= 3 x 13
= 39
(b)
100¢ = $1
Total value of the 50-cent coins in David's glass jar
= 39 x 50
= 1950¢
= $19.50
Answer(s): (a) 39; (b) $19.50