There are 4 times as many nickels as dimes in a coin bag. The coins have a total value of 600 cents ($6.00). Find the number of nickels. Write and solve an equation to do so.

(i found the answer through guess and check but i need to know the equation....btw the answer is 80 nickels and 20 dimes....plz help me find the equation)

1 answer

Let n be the number of nickels
d the number of dimes

n = 4d because we are told "4 times as many nickels as dimes"

The total value is:

n * 5 + d * 10 = 600

Divide across by 5:

n + 2d = 120

and n=4d, so

4d + 2d = 120

6d = 120
d= 20

So n = 4d = 80