SOLUTION: Dan the Driver travels at 50 km at 80 km/h, 30 km at 60 km/h, and 80 km at 100 km/h. Find Dan's average speed in km/h.

Algebra ->  Average -> SOLUTION: Dan the Driver travels at 50 km at 80 km/h, 30 km at 60 km/h, and 80 km at 100 km/h. Find Dan's average speed in km/h.      Log On


   

Question 1199430: Dan the Driver travels at 50 km at 80 km/h, 30 km at 60 km/h, and 80 km at 100 km/h. Find Dan's average speed in km/h.
Answer by ikleyn(52781) About Me  (Show Source):
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Dan the Driver travels at 50 km at 80 km/h, 30 km at 60 km/h, and 80 km at 100 km/h.
Find Dan's average speed in km/h.
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The average speed is the total distance divided by the total time

    average speed = %2850+%2B+30+%2B+80%29%2F%2850%2F80+%2B+30%2F60+%2B+80%2F100%29 = 160%2F%285%2F8+%2B+1%2F2+%2B+4%2F5%29 = 

                  = 160%2F%28%285%2A5%29%2F40+%2B+20%2F40+%2B+%284%2A8%29%2F40%29 = 160%2F%28%2877%2F40%29%29 = %28160%2A40%29%2F77 = 6400%2F77 = 83.169 km/h  (rounded).   ANSWER

Solved.