8C Retake Assignment

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?

Joan can clean the store in five hours. If Dan helps, it takes them four hours. Without help, how long would it take Dan to complete this job ?

• 10

• 25

• 20

• 15

• no solution

• x = 2

• x = -2

• x = 8

A train traveled 240 kilometers at a certain speed. When the engine was replaced by an improved model, the speed was increased by 20 km/hr and the travel time for the trip was decreased by 1 hour. What was the rate of the improved engine? (only put the number - no units!)