Question

There are $3.90 worth of nickles and quarters in a piggy bank. There are 6 more quarters than nickels.

How many of each coin are in the piggy bank?



Enter your answers in the boxes.

_____ nickels and ____ quarters

Answer 1

Answer: There are 8 nickels and 14 quarters.

Step-by-step explanation:

Since we have given that

there are $3.90 worth of nickles and quarters in a piggy bank.

Let the number of nickles be x

Let the number of quarters be x+6

As we know that

`1\ nickle=0.05\ dollars\\\\and\\\\\ 1\ quarter=0.25\ dollars`

According to question,

`0.05x+0.25(x+6)=3.90\\\\0.05x+0.25x+1.5=3.90\\\\0.3x=3.90-1.5\\\\0.3x=2.4\\\\x=(2.4)/(0.3)=8\\\\and \\\\x+6=8+6=14`

Hence, there are 8 nickels and 14 quarters.

Answer 2

For this case, the first thing we must do is define variables.

We have then:

x: number of nickles

y: number of quarters

We now write the system of equations.

We have then:

`image`

Solving the system of equations graphically we have:

`image`

Answer:

8 nickels and 14 quarters

Note: see attached image for the graphic solution.