Math
posted by Angie on .
You have a total of 21 coins, all nickels and dimes. The total value is $1.70. Write and solve a system of equations to find the number of dimes d and the number of nickels n that you have.
I already wrote the equations: n+d=21 and 10d+5n=1.70. But I don't know how to solve it..

You have a total of 21 coins, all nickels and dimes. The total value is $1.70. Write and solve a system of equations to find the number of dimes d and the number of nickels n that you have.
I already wrote the equations: n+d=21 and 10d+5n=1.70. But I don't know how to solve it.
1n+d=21
210d+5n=170
3From (1), d=21n
4Substitute into (2) and solve for n and then d. 
i get it..thanks!