Two rifles are fired from the same place at a difference of 11 minutes 45 seconds. But a man who is coming towards the place in a train hears the second sound after 11 minutes. Find the speed of train. (speed of sound = 330 m/s)
A. 72 kmph
B. 36 kmph
C. 81 kmph
D. 108 kmph
E. None of these
Answer: Option C
Solution(By Examveda Team)
Distance travelled by man-train in 11 minute = distance traveled by sound in (11 min 45 sec - 11 min) = 45 sec. Let the speed of train be x kmph. Now, Or, $$x \times \frac{{11}}{{60}} = \frac{{45}}{{3600}} \times 330 \times \frac{{18}}{5}$$ Or, x = 81 kmph.This Question Belongs to Arithmetic Ability >> Speed Time And Distance
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Comments ( 3 )
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Need more explanation
Actually, here is concept of relative speed of Man-Train and Sound. It also includes relative time. See, both are approaching to each other it means the must be subtracted. To find the relative time as we do in relative speed.
Please explain how it happens " distance travelled by man train in 11 minute=distance traveled by sound in (11min45-11min)"