Dollar Bills and system of two linear equations

by Kendall Whiteside
(Happy Valley, Oregon)

“A student has some $1 bills and $5 bills in his wallet. He has a total of 15 bills that are worth $47. How many of each type of bill does he have? ”

Let x be the number of $1 bills and y be the number of $5 bills.

The number of $1 bills plus the number of $5 bills equal 15 or x + y = 15

Worth of $1 bills plus worth of $5 bills = $47 or 1x + 5y = 47


Therefore, just solve the system of equations below.

x + y = 15 (1)

x + 5y = 47 (2)


(2) minus (1) will give 4y = 32

y = 8 since 4 × 8 = 32

x + 8 = 15

x = 7

The student has seven $1 bills and eight $5 bills.


Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Algebra word problems.

Recent Articles

  1. Probability Line - Definition and Examples

    Nov 21, 19 02:38 PM

    What is a probability line ? Things that you must know before doing problems ...

    Read More

New math lessons

Your email is safe with us. We will only use it to inform you about new math lessons.

                                 Follow me on Pinterest

Real Life Math Skills

Learn about investing money, budgeting your money, paying taxes, mortgage loans, and even the math involved in playing baseball.