Please enter the following details
Two persons are walking beside a railway track at respective speeds of 2 and 4 km per hour in the same direction. A train came from behind them and crossed them in 90 and 100 seconds, respectively. The time, in seconds, taken by the train to cross an electric post is nearest to
Let the length of the train be $$ l kms$$ and speed be $$ s kmph$$. Base on the two scenarios presented, we obtain:
$$\frac{l}{s-2}=\frac{90}{3600}$$....(i) andĀ $$\frac{l}{s-4}=\frac{100}{3600}$$...(ii)
On dividing (ii) by (i) and simplifying we acquire the value of $$s$$ asĀ $$22 kmph$$. Substituting this value in (i), we haveĀ $$l=\frac{90}{3600}\times\ 20\ kms$$ {keeping it in km and hours for convenience}
Since we need to findĀ $$\frac{l}{s}$$, let this be equal to $$x$$. Then,Ā $$x\ =\ 90\times\frac{20}{22}\ =81.81\ \approx\ 82\ \sec onds\ $$
Hence, Option B is the correct choice.
Video Solution
Your Doubts
Drop Your File Here!
Ask Your Doubt
Drop Your File Here!
Create a FREE account and get:
- All Quant CAT complete Formulas and shortcuts PDF
- 38+ CAT previous year papers with video solutions PDF
- 5000+ Topic-wise Previous year CAT Solved Questions for Free
