Answer:
There can’t be only dimes.
There can be 17 nickels.
Explanation:
Dimes count by 10. Therefore, you can’t get to 85 by using dimes.
10, 20, 30, 40, 50, 60, 70, 80, 90, 100
As you can see, there is no 85.
If the jar contained only nickels, then it will have 17 nickels.
(17 times 5 is 85)