Question 1168816
N = number of 5 cent coins
D = number of 10 cent coins


N = D/2 + 7
5N + 10D = 535


Plug in the first equation into the second.

5(D/2 + 7) + 10D = 535

25D/2 = 500

D = 40


There were 40 10-cent coins and {{{27}}} 5 cent coins.