Math Algebra 7.2.2.2

9. For every 12 hours Nan works, he makes 84 dollars. If x represents the hours Nan works and y represents the amount of money he makes, what is the value of k in the equation y = kx?

10. A store is having a promotion where all items are 25% off. In addition, they offer a coupon that takes an additional 10% off the sale price. If Elisa buys a shirt that originally cost $40.00 and applies the coupon towards her purchase, how much will she pay for the shirt?

11. Aaron and Jenny live in different states. The sales tax rate in Aaron’s state is 10%. The sales tax rate in Jenny’s state is 8%. If Aaron buys a car for 12,000 dollars and Jenny buys a car for $15,000, how much more will Jenny pay in taxes than Aaron?

12. In 3rd grade, Mollie’s class had 25 students. In 4th grade, her class size increased 20 percent from the year before. In 5th grade, her class size decreased 20 percent from the year before. How many students were in Mollie’s 5th grade class?