Rational Equations Work Problems

Which of the following equations makes the most sense for the following situation: Jerry works twice as fast as Kenny. If Jerry works for 2 hours and is then joined by Kenny...and they work an additional 3 hours...how fast could they each do the job alone?

Identify the LCD.

• x²(x - 2)

• x(x - 2)

• x

• (x - 2)

Solve for x

Katherine can paint a room in 4 hours. Joe needs 6 hours to paint the same room. Which equation would you use to determine how long it takes them to paint the room if they work together?

A boat goes 10 miles downstream in the same time it can go 3 miles upstream. The speed of the current is 2 miles per hour. Which equation could you use to find the speed of the boat in still water?

A plane flies 1225 miles with a tailwind in the same time it can go 1100 miles against the wind. The speed of the plane in still air is 575 miles per hour. Which equation would you use to find the speed of the wind?

A car travels 400 km in the same time that a freight train travels 300 km. The speed of the car is 25 km/h more than the speed of the train. Find the speed of the car and the speed of the train. (Hint set fractions equal rather than adding to a set time.)

The time it takes for a canoe to go 4 miles upstream and back 4 miles downstream is 5 hours. The current in the lake is 2 mile per hour.  Find the average speed (rate) of the canoe in still water.

• 16.92 minutes

• 15 minutes

• 16.41 minutes

• 11.07 minutes