Bob drove from home

Question

Bob drove from home to work at 60 mph. After work the traffic was heavier, and he drove home at 50 mph. His driving time to and from work was 1 hour and 28 minutes. How far does he live from his job?

Answer 1

Distance = Rate x Time

 

28 minutes  = 28/60 hours, because there is 60 minutes per hour.

                  = 14/30 hour

                  = 7/15

 

So 1 hour and 28 minutes of driving = 1 and 7/15 hour = 22/15 hours

 

D = 60 x T

 

D = 50 mph  x (22/15 - T)

 

60 T = 50*(22/15 - T)

 

60T = 1100/15 - 50 T

 

110 T = 1100/15

 

1650 T = 1100

 

T = 1100/1650

 

  = 110/165

 

  = 22/33

 

 = 2/3

 

2/3 of an hour is 40 minutes

 

He drove 60 miles per hour to work for 40 min = 2/3 hour.

The distance to work is 60 x 2/3 = 120/3 = 40 miles.

 

Coming home, he drove the same 40 miles for 

  22/15 - 2/3 = 22/15 - 10/15 = 12/15 = 4/5 hr = 4/5 x 60 = 48 minutes.

 

The total time is 40 minutes + 48 minutes = 88 minutes

                                                              = 1 hour and 28 minutes.

 

He lives 40 miles from his job