ABC26GN3890 · Problems on Trains

Subject: General Aptitude · Chapter: Problems on Trains · Exam: 2002 · Marks: · Difficulty:

Two trains are moving in opposite directions @ 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is
(a)36
(b)45
(c)48
(d)49
Answer
Answer (as printed): C
Explanation
Relative speed $=(60+90) \mathrm{km} / \mathrm{hr}$ $$=\left(150 \times \frac{5}{18}\right) \mathrm{m} / \mathrm{sec}=\left(\frac{125}{3}\right) \mathrm{m} / \mathrm{sec} .$$ Distance covered $=(1.10+0.9) \mathrm{km}=2 \mathrm{km}=2000 \mathrm{m}$. $$\text { Required time }=\left(2000 \times \frac{3}{125}\right) \mathrm{sec}=48 \mathrm{sec} .$$

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