Answer: the jar contains 73 dimes and 106 nickels.
Explanation:
The worth of a dime is 10 cents. Converting to dollars, it becomes
10/100 = $0.1
The worth of a nickel is 5 cents. Converting to dollars, it becomes
5/100 = $0.05
Let d represent the number of dimes in the jar.
Let n represent the number of nickels in the jar.
There is a total of 179 coins in the jar. This means that
d + n = 179
The value of the coins is $12.60. This means that
0.1d + 0.05n = 12.6 - - - - - - - - - - - 1
Substituting d = 179 - n into equation 1, it becomes
0.1(179 - n) + 0.05n = 12.6
17.9 - 0.1n + 0.05n = 12.6
- 0.1n + 0.05n = 12.6 - 17.9
- 0.05n = - 5.3
n = - 5.3/-0.05
n = 106
d = 179 - 106
d = 73