Solving Problems Involving Proportions

Mixing Paint

Work Time

Mixing Paint

Carlos mixed some green paint by using 4 cups of blue paint and 3 cups of yellow paint. He used all of the green paint and wants to make some more. How many cups of blue paint should he mix with 5 cups of yellow paint to get the same color green?

  • Choose a variable to represent what you want to find out.
  • Write an equation that you can use to solve the problem.
  • Solve the equation.
  • Think about your answer. Does it make sense? Explain.


  • What proportion represents the problem?
  • Where will you put the 5 in the proportion?
  • What will you multiply or divide by to make the equation easier to work with?