There are 138 quarters and nickels in all. The combined value of the quarters and nickels is $34.50. How many quarters are there? What is the value of the nickels?

Respuesta :

Answer:

There 138 quarters and 0 nickels.

The value of nickels is $0.

Step-by-step explanation:

A quarter is 0.25 of a dollar, and a nickel is 0.05 of a dollar. We are told that the total worth of nickels and dollars we have is 34.5, that is

[tex]0.25q+0.05n=34.5[/tex]

where [tex]q[/tex] is the number of quarters, and [tex]n[/tex] is the number of nickels.

We are also told that total number of coins is 138, that is

[tex]q+n=138[/tex]

so we have two equations:

[tex](1).\:0.25q+0.05n=34.5[/tex]

[tex](2).\:q+n=138[/tex]

To this system of equations we first solve for [tex]n[/tex] in second equation and substitute its value into the first equation:

[tex]n=138-q[/tex]

the first equation becomes

[tex]0.25q+0.05(138-q)=34.5[/tex]

[tex]0.2q+6.9=34.5[/tex]

[tex]\boxed{q=138}[/tex]

So we have 138 quarters.

Now we put this value into equation(2) and solve for [tex]n[/tex]

[tex]n+138=138[/tex]

[tex]\boxed{n=0}[/tex]

So we have 0 nickles and therefore their value is $0.