2. » The ratio of boys to girls in a twelth-grade class at a high school is about 3 to 2. There are about 600 twelfth-graders. How many are boys? How many are girls?

3. » Use a system of linear equations to solve the problem. » Define ˃b=the number of boys ˃g=the number of girls » Relate ˃The total number of twelfth-graders is 600. ˃b + g = 600

5. Solve for b. Use the first equation. Substitute for b. Combine like terms. Solve for g.

6. Substitute 240 for g. Multiply both sides by 240. There are about 360 twelfth- grade boys and 240 twelfth- grade girls.

7. » Suppose a paper manufacturer publishes a newsletter. Expenses are $.90 for printing and mailing each copy, plus $600 for research and writing. The price of the newsletter is $1.50 per copy. How many copies of the newsletter must the company sell to break even? Define

8. » Suppose a paper manufacturer publishes a newsletter. Expenses are $.90 for printing and mailing each copy, plus $600 for research and writing. The price of the newsletter is $1.50 per copy. How many copies of the newsletter must the company sell to break even? Expenses Income

9. » Choose a method to solve the system. Use substitution since it is easy to substitute for y using these equations. Substitute 1.5x for y in the first equation. Subtract 0.9x from each side. Divide each side by 0.6.