Advertisements
Advertisements
Question
A train goes from Gandhinagar to Patna at a speed of 128 kmph and returns to Gandhinagar at a different speed. If the average speed for the entire journey is l 12 kmph, then find the speed of the train for the return journey (to nearest kmph)
Options
96 kmph
192 kmph
48 kmph
None of these
MCQ
Advertisements
Solution
None of these
Explanation:
We know Average Speed = `"total distance"/"total time"`
In case distance is same then we can use the SHORT CUT METHOD
Average speed = `(2xy)/(x + y)` ......(where x, y are speed)
⇒ 112 = `(2 xx 128 xx y)/(128 + y)`
⇒ 14336 + 112 y = 256 y
⇒ y = 99.99 or 100 kmph
shaalaa.com
Time, Speed and Distance (Entrance Exam)
Is there an error in this question or solution?
