Answer: the jar contains 29 dimes and 25 quarters.
Step-by-step explanation:
The worth of a dime is 10 cents. Converting to dollars, it becomes
10/100 = $0.1
The worth of a quarters is 25 cents. Converting to dollars, it becomes
25/100 = $0.25
Let x represent the number of dimes contained in the jar.
Let y represent the number of quarters contained in the jar.
A jar containing only dimes and quarters contains a total of 54 coins.. This means that
x + y = 54
The value of all the coins in the jar is $9.15. This means that
0.1x + 0.25y = 9.15 - - - - - - - - - - - 1
Substituting x = 54 - y into equation 1, it becomes
0.1(54 - y) + 0.25y = 9.15
5.4 - 0.1y + 0.25y = 9.15
- 0.1y + 0.25y = 9.15 - 5.4
0.15y = 3.75
y = 3.75/0.15 = 25
x = 54 - y = 54 - 25
x = 29
