# You have a total of 21 coins, all nickels and dimes. The total value is $1.70. How many nickels and how many dimes do you have?

##### 1 Answer

The number of nickels is

#### Explanation:

Representing the nickels as

#n+d=21# #5n+10d=170#

We use the first equation to derive a value for

Subtract

We now simplify the second equation by dividing all terms by

Using the value for

Open the brackets and simplify.

Subtract

In the first equation, substitute

Subtract

Thus, the number of nickels is