You save 42 nickels and dimes that total 3.35 how many nickels and dimes do you save?

Answer 1

This problem can be solved using a system of equations.

If we call the number of nickles n and the number of dimes d, we can write the following two equations:

n + d = 42 (The number of nickels and dimes is 42)

.05n + .1d = 3.35 (5 cents for every nickel plus 10 cents for every dime is $3.35)

Then:

n + d = 42

5n + 10d = 335 (Switch to cents instead of dollars, gets rid of decimals)

n = 42 - d

We have now just defined n in terms of d. Now every time you see n in the second equation, you can replace it. This is called substitution.

5n + 10d = 335 (from above)

5(42 - d) + 10d = 335 (substituting for n)

Follow through with the algebra, and d (# of dimes) = 25, then there must be 17 nickels.

25 dimes, 17 nickels