Question

Newton has 10 more dimes than nickels. He has
twice the number of quarters than nickels. If he
has $6.20, how many of each coin does he have?

Answer 1

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.

$x\times 0.05+(x+10)\times 0.10+2x\times 0.25=6.20$

$0.05x+0.10x+1+0.50x=6.20$

$0.65x=6.20-1$

$0.65x=5.20$

Divide both sides by 0.65.

$x=\dfrac{5.20}{0.65}$

$x=8$

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.