Question : Train A running at 81 km/hr takes 72 sec to overtake train B, when both the trains are running in the same direction, but it takes 36 sec to cross each other if the trains are running in the opposite direction. If the length of train B is 600 metres, then find the length of train A (in metres).
Option 1: 600
Option 2: 480
Option 3: 590
Option 4: 900
Latest: SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL complete guide
New: Unlock 10% OFF on PTE Academic. Use Code: 'C360SPL10'
Correct Answer: 480
Solution : Let the length of train A be $L{_A}$ and the speed of train B be $S{_B}$ km/hr. When both trains are running in the same direction, Distance = relative speed $\times$ time ⇒ $L{_A}+600 = (81-S{_B})\times\frac{5}{18}\times 72$ ⇒ $L{_A}+600 = (81-S{_B})\times 20$ ⇒ $L{_A}+20S{_B} = 1020$ ........(1) When both the trains are running in the opposite direction, ⇒ $L{_A}+600 = (81+S{_B})\times\frac{5}{18}\times 36$ ⇒ $L{_A}+600 = (81+S{_B})\times 10$ ⇒ $L{_A}-10S{_B} = 210$ Multiplying by 2 we get, ⇒ $2L{_A} - 20S{_B} = 420$ ⇒ $20S{_B} = 2L{_A} -420$........(2) Now, putting the value from equation (2) in (1), we get, ⇒ $L{_A} + 20S{_B} = 1020$ ⇒ $L{_A} + 2L{_A} - 420 = 1020$ ⇒ $3L{_A} = 1440$ ⇒ $L{_A} = 480\ \mathrm{m}$ Hence, the correct answer is 480.
Candidates can download this ebook to know all about SSC CGL.
Answer Key | Eligibility | Application | Selection Process | Preparation Tips | Result | Admit Card
Question : Two trains are moving in the same direction at 36 km/hr and 48 km/hr. The time taken by the faster train to cross a man sitting in the slower train is 33 seconds. What will be the length of the faster train?
Question : A train of length 100 metres crosses another train of length 150 metres, running on a parallel track in the opposite direction, in 9 seconds. If the speed of a train having a length of 150 metres is 40 km/h, then what is the speed (in km/h) of the other train?
Question : A train running at 70 km/hr crosses another train running in the same direction at 34 km/hr in 25 seconds. What is the combined length of both trains (in metres)?
Question : Two trains are moving in the opposite direction at the speed of 48 km/hr and 60 km/hr respectively. The time taken by the slower train to cross a man sitting in the faster train is 12 seconds. What is the length of the slower train?
Question : Train B, speeding at 100 km/hr, crosses another train C, running in the same direction, in 2 minutes. If the lengths of trains B and C are 150 metres and 250 metres, respectively, what is the speed of train C (in km/h)?
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile