Subject: General Aptitude · Chapter: Problems on Trains · Exam: · Marks: · Difficulty:
A train passes two bridges of lengths 500 m and 250 m in 100 seconds and 60 seconds respectively. The length of the train is [SSC-CHSL (10+2) Exam, 2015]
(a)152 m
(b)125 m
(c)250 m
(d)120 m
Answer
Answer (as printed): B
Explanation
Let the length of train $x \mathrm{m}$ $$\text { Speed of train }=\frac{\text { (Length of train }+ \text { length of bridge) }}{\text { Time taken in crossing }}$$ According to information we get $$\Rightarrow \frac{x+500}{100}=\frac{x+250}{60}$$ $\Rightarrow 60(x+500)=100(x+250)$ $$3(x+500)=5(x+250)$$ $\Rightarrow 5 x+1250=3 x+1500$ $$\Rightarrow 5 x-3 x=1500-1250$$ $\Rightarrow 2 x=250$ $$\Rightarrow x=\frac{250}{2}=125 \mathrm{m}$$