intermediate algebra
posted by jr .
joe has a collection of nickles and dimes that is worth $3.95. if the number of dimes was doubled and the number of nickles was increased by 21, the value of the coins would be $8.40. How many nickles and dimes does he have? show all your work.
help me please

5n + 10d = 395
5(n+21) + 10(2d) = 840
now just solve for n and d:
34 dimes
11 nickels