Mathematics

Mathematics

Problem

A bus travels 1st 150 km with 25 kmph, next 200 km with 50 kmph. What must its speed in last 150 km such that the net average speed for 500 km is 20 kmph (1) 10 kmph (2) 15 kmph (3) 20 kmph (4) 25 kmph (1) 10 kmph (2) 15 kmph (3) 20 kmph (4) 25 kmph
Intuitive explanation

Average speed is total distance divided by total time—not the average of the speeds. Find the time for each segment using time=distancespeed\text{time} = \frac{\text{distance}}{\text{speed}}, then set up an equation where the total time gives you the required average. The unknown speed in the last segment is what you'll solve for.

Intuitive explanation

Average speed is total distance divided by total time—not the average of the speeds. Find the time for each segment using time=distancespeed\text{time} = \frac{\text{distance}}{\text{speed}}, then set up an equation where the total time gives you the required average. The unknown speed in the last segment is what you'll solve for.

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