Miscellaneous Question 26
- At its usual speed, a train of length L metres crosses platform 300 metre long in 25 seconds. At $50 \%$ of its usual speed, the train crosses a vertical pole in 20 seconds. What is the value of $L$ ?
(1) 160
(2) 260
(3) 200
(4) 310
(5) 350
(IBPS RRBs Officer CWE (Pre.) 14.11.2016 (Shift-III))
Show Answer
Correct Answer: 26. (3)
Solution: 26. (3) Distance covered by train in crossing the platform
$=(\mathrm{L}+300)$ metre
$\therefore$ Speed of train
$=\left(\frac{\mathrm{L}+300}{25}\right)$ metre/second
Case II, $\frac{1}{2}\left(\frac{\mathrm{L}+300}{25}\right)=\frac{\mathrm{L}}{20}$
$\Rightarrow \frac{\mathrm{L}+300}{50}=\frac{\mathrm{L}}{20}$
$\Rightarrow 5 \mathrm{L}=2 \mathrm{L}+600$
$\Rightarrow 3 \mathrm{L}=600$
$\Rightarrow \mathrm{L}=\frac{200}{3}=200$ metre
BETA
