For this item, we let x be the number of dimes and y be the number of nickels. The sum of these numbers should be 147.
x + y = 147
Also, the equivalent of a dime is 10 cents and that of nickel is 5 cents. The equation that would best represent this is,
0.1x + 0.05y = 11.65
The values of x and y are 86 and 61, respectively.