Solve each problem. 10. The sum of two numbers is 23. If one of the numbers is halved, the sum will
become 17. What are the numbers?
11. The perimeter of a rectangle is 60 cm. The length is four times the width. What
are the length and the width of the rectangle?
Write a system of equations to model each situation. Solve by any method.
12. Sarah is 25 years older than her son Gavin. In ten years, Sarah will be twice
Gavin's age. How old are Sarah and Gavin now?
Yen chemist is mixing a solution that is 2% acid and another solution that is 8%
acid. She needs to make 75 mL of a solution that is 5% acid. How much of each
solution should she use?