Let d = number of dimes
Let n = number of nickels
d + n = 1530
A dime is worth $0.10. d dimes are worth 0.1d.
A nickel is is worth $0.05. n nickels are worth 0.05n.
0.1d + 0.05n = 127.45
Solve the first equation for d and substitute into the second equation.
d = 1530 - n
0.1(1530 - n) + 0.05n = 127.45
153 - 0.1n + 0.05n = 127.45
-0.05n = -25.55
n = 511
Now substitute this value in the first original equation.
d + n = 1530
d + 511 = 1530
d = 1019
He has 511 nickels and 1019 dimes.