System of Equations Word Problem Examples

Instructor: Mia Primas

Mia has taught math and science and has a Master's Degree in Secondary Teaching.

Most word problems require that you find the value of one variable. But what if there is more than one unknown variable? In this lesson, you will use systems of equations and solve word problems that have more than one unknown value.

Getting Paid

Systems of equations have two or more equations with two or more variables that are solved simultaneously. The goal is to find a value for each variable that satisfies the equations. In the following examples, we will create systems of equations based on the word problems. We will then use substitution and elimination strategies to solve them.

  • Example 1: My younger cousins worked part-time jobs over the summer to save money for a car. The job paid different rates for working weekdays and weekends. During the first week, one cousin worked 22 hours during the week and one hour on the weekend, earning $232. Her sister earned $270 by working 15 hours during the week and 10 hours on the weekend. What was the hourly pay rate for working weekdays and weekends?

When solving word problems, it is important to understand what you are asked to find. This problem is asking us to find the hourly pay rate for weekdays and the hourly pay rate for weekends. We will need to use different variables to represent each unknown. Let's use x for the weekday rate and y for the weekend rate. Now we can use the other information from the word problem to create equations that we will use to solve for the variables.

One cousin worked 22 weekday hours and one weekend hour for a total of $232. We can represent this with the equation 22x + y = 232. Using the pay for the other cousin, we get the equation 15x + 10y = 270. Since there are two equations with the same two variables, we can set them up as a system of equations and solve them simultaneously.

System of equations for example 1

The system of equations can be solved using the substitution method. This involves using an expression from one equation to substitute for one of the variables in the other equation. The first equation can be solved for y by subtracting 22x from both sides of the equation. This leaves us with y=232 - 22x. Since y is equal to the expression 232 - 22x, we can substitute the expression for y in the second equation. The equation becomes 15x + 10(232-22x) = 270. We now have one equation with one variable to solve.

Solving the system of equations using substitution

We now know that the hourly pay rate for weekdays is ten dollars. By substituting ten for x in one of the equations, we can solve for y. Using the revised version of the first equation, we get y = 232 - 22(10) = 12.

Now that the values of both variables are known, the word problem is solved. The hourly pay rate is ten dollars for weekdays and twelve dollars for weekends.

Fundraiser Sales

  • Example 2: A high school soccer team held a fundraiser to raise money for new uniforms. They sold cookies and flavored popcorn. On the first day, they sold 44 bags of popcorn and 32 boxes of cookies for a total of $97. On the second day, they raised $179 by selling 68 bags of popcorn and 64 boxes of cookies. How much did they charge for each cookie and bag of popcorn?

In this problem, we are asked to find two things: the price for a box of cookies and the price for a bag of popcorn. We can use c to represent the price for a box of cookies and p to represent the price for a bag of popcorn. Next we can use the information in the word problem to set up equations that will help us find the values of the variables.

To unlock this lesson you must be a Study.com Member.
Create your account

Register for a free trial

Are you a student or a teacher?
I am a teacher

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back

Earning College Credit

Did you know… We have over 95 college courses that prepare you to earn credit by exam that is accepted by over 2,000 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it free for 5 days!
Create An Account