Bob drove from City P to City Q. He traveled the fist 36km at an average speed of 54km/h. He traveled the remaining 96km at a average speed of 72km/h. Find his average speed for the whole trip.

2 câu trả lời

The first 36km travel time is:   
36 : 54 = 2/3 (hours)
Time left to go is:
96 : 72 = 4/3 (hours)
The average velocity of the entire distance is:

2/3 + 4/3 = 2 (hours)
The average speed of the entire trip is:
(36 + 96) : 2 = 66 (km/h)

Answer: 66 km/h

Time to go the first distance is:

      `36: 54 = 2/3` hours

Time left to go the remaining distance is:

       `96: 72 = 4 / 3` h
His average speed for the whole trip is:

       `2/3 + 4/3 = 2` hours

Average speed of the whole trip is:

          `(36 + 96): 2 = 66` (km / h)

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