Bob's speed --- x km/h
Al's speed ----- 1.1x km/h
Bob's time = 264/x and Al's time = 264/1.1x
the difference in their times is 18 min = 18/60 hours
264/x - 264/1.1x = 18/60 = 3/10
multiply each term by 110x , and take over to solve for x
comes out nice.
Al and Bob, who live in North Vancouver, are Seattle Mariners fans. They regularly drive the 264km from their home to the ballpark in Seattle. On one particular day, Bob drove to the game. On the return journey, Al was able to increase their average speed by 10% and save 18 minutes on travelling time. Calculate the average speed at which Bob drove to the game.
1 answer