we need to divide the total cents by the amount of coins so that we know how much each coin is worth:
75/5 = 15
but there aren't coins worth 15 cents.
So lets accomodate the total in known coins:
1 cent, 5 cents, 10 cents, 25 cents, 50 cents.
take this combination:
2(25) + 2(10) + 1(5) = 50 + 20 + 5 = 75
so she could have 2 coins of 25 cents, and 2 coins of 10 cents, and 1 coin of 5 cents