Given:
Newton has 10 more dimes than nickels.
He has twice the number of quarters than nickels.
Total amount he has = $6.20.
To find:
The number of each coin.
Solution:
Let the number of nickels be x.
Newton has 10 more dimes than nickels.
Dimes = x+10
He has twice the number of quarters than nickels.
Quarters = 2x
We know that, 1 nickel = $0.05, 1 dime = $0.10 and 1 quarter = $0.25.
Total amount he has is $6.20.




Divide both sides by 0.65.


Now,
Number of nickels = 8
Number of dimes = 8 + 10 = 18
Number of quarters = 2(8) = 16
Therefore, the number of nickels, dimes and quarters are 8, 18 and 16 respectively.