Question 51912
If N is nickles and D is dimes then N+D=40 because Kandi has 40 coins.
If we solve this equation for N we get:
N+D-N=40-N
D=40-N
So the number of dimes we have is 40-N
and the number of nickles we have is N

The amount of money we have is equal to the worth of the coin times the number of coins.  I like to solve these equations in terms of cents rather than dollars because it eliminates the decimals.

The amount of money we have in dimes is 10(40-N).
The amount of money we have in nickles is 5N.
The total amount of money we have is 265 (in cents).

Therefore, (the amount of money in dimes)+(the amount of money in nickles)=(total) becomes:
10(40-N)+5N=265
400-10N+5N=265
400-5N=265
-400+400-5N=265-400
-5N=-135
-5N/-5=-135/-5
N=27
Thus, Kandi had 27 nickels.