I need help with this.

Question

A piggy bank contains some dimes and nickels. There are eight more dimes and nickels in the bank. There is a total of $1.40. How many of each type of coin are in the bank?

Answer 1

D=8+N

10D+5N = 140

10(8+N)+5N = 140

80+10N +5N = 140

15N = 140-80= 60

N = 60/15 = 4 nickels

D = 8+4 = 12 dimes

12(10)+ 4(5) = 140