## Practice questions

- Luz filled up her 10-gallon gas tank with regular unleaded fuel for $30. Tony used premium fuel, which costs 25 percent more per gallon, to fill his 10-gallon gas tank. Assuming both of their gas tanks were empty, how much did Tony spend?
**A.**$37.75**B.**$3.75**C.**$37.50**D.**$30 - If one side of a square is increased by 6 cm and an adjacent side is decreased by 2 cm, a rectangle with a perimeter of 28 cm is formed. What is the area of the rectangle?
**A.**19 cm^{2}**B.**25 cm^{2}**C.**31 cm^{2}**D.**33 cm^{2}

## Answers and explanations

- The correct answer is
**Choice (C).**Write an equation that lets

*x*represent the cost of 1 gallon of unleaded fuel. Ten gallons cost Luz $30, soBecause premium fuel costs 25 percent more, it costs 125 percent of the price of unleaded fuel, so let 1.25

*x*represent the amount Tony spent per gallon. Unleaded gas costs $3 per gallon, so figure out how much Tony spent per gallon by replacing*x*in his equation with 3:$3(1.25) = $3.75

Each gallon of premium fuel costs $3.75 and Tony bought 10 gallons, so multiply 3.75 by 10 to find out how much Tony spent:

Tony spent $37.50 on fuel.

- The correct answer is
**Choice (D).**This problem requires you to take a few steps to arrive at the answer.

Create a table that lets you visualize what to use in your equation, letting

*x*represent the length of one side of the square:The problem gives you the perimeter of the rectangle, so use the perimeter formula to find the dimensions — you'll need them to find the rectangle's area. Remember that

*P*= 2*l*+ 2*w*, where*P*represents perimeter,*l*represents length, and*w*represents width:Now you know that the original square's sides each measured 5 centimeters. As the problem tells you, one side was increased by 6 centimeters to create the rectangle, while the other was decreased by 2 centimeters. That makes one side 11 centimeters and the other 3 centimeters. You can find the area of the rectangle with the formula

*A*=*lw*, where*A*represents the area,*l*represents the length, and*w*represents the width:The rectangle's area is 33 square centimeters.