5N + 10*(16-N) = 125 cents ( "Money" equation ) ( N = # of nickels ) ============> divide by 5 both sides =================> N + 2*(16-N) = 25 N + 32 - 2N = 25 N - 2N = 25 - 32 -N = -7 =====> N = 7. Answer. 7 nickels and 16-7 = 9 dimes.