Question

A piggy bank contains $2.65 in nickels and dimes. If the number of nickels is 7 less than three times the number of dimes, how many of each kind of coin are there?

Answer 1

The number of nickels is 29 and the number of dimes is 12

Explanation:

Let

x -----> the number of nickels

y ----> the number of dimes

Remember that

1 nickel=$0.05

1 dime=$0.10

we know that

0.05x+0.10y=2.65 -----> equation A

x=3y-7 ------> equation B

Solve the system by graphing

The solution of the system is the intersection point both graphs

The solution is the point (29,12)

see the attached figure

therefore

The number of nickels is 29 and the number of dimes is 12