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Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tunnel of length ‘L’ in parallel tracks from opposite directions with velocities 108 km/h and 72 km/h, respectively. If train ‘A’ takes 35s less time than train ‘B’ to cross the tunnel then, length ‘L’ of tunnel is (Given L = 60 l) (1) 1200 m (2) 2700 m (3) 1800 m (4) 900 mRead more on Sarthaks.com - https://www.sarthaks.com/3492985/two-trains-and-length-and-are-travelling-into-tunnel-length-parallel-tracks-from-opposite?
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Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tu...
Problem Overview
We have two trains, A and B, moving towards each other in a tunnel. The following details are provided:
- Length of Train A = l
- Length of Train B = 4l
- Length of the tunnel = L (Given L = 60l)
- Velocity of Train A = 108 km/h
- Velocity of Train B = 72 km/h
- Time difference = 35 seconds

Convert Velocities to m/s
- Train A:
\[ 108 \text{ km/h} = \frac{108 \times 1000}{3600} = 30 \text{ m/s} \]
- Train B:
\[ 72 \text{ km/h} = \frac{72 \times 1000}{3600} = 20 \text{ m/s} \]

Time Taken by Each Train to Cross the Tunnel
- **Time for Train A (TA):**
\[ TA = \frac{L + l}{30} \]
- **Time for Train B (TB):**
\[ TB = \frac{L + 4l}{20} \]

Equation Setup
From the problem, we know:
\[ TA = TB - 35 \]
Substituting the expressions for TA and TB:
\[ \frac{L + l}{30} = \frac{L + 4l}{20} - 35 \]

Clearing the Equation
Multiply through by 60 (LCM of 30 and 20):
\[ 2(L + l) = 3(L + 4l) - 2100 \]
Simplifying gives:
\[ 2L + 2l = 3L + 12l - 2100 \]
Rearranging:
\[ L + 10l = 2100 \]
Substituting \( L = 60l \):
\[ 60l + 10l = 2100 \]
Thus:
\[ 70l = 2100 \]
Solving for l:
\[ l = 30 \text{ m} \]

Finding Length of the Tunnel
Now substituting back to find L:
\[ L = 60l = 60 \times 30 = 1800 \text{ m} \]

Final Answer
The length of the tunnel is:
**(3) 1800 m**
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Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tunnel of length ‘L’ in parallel tracks from opposite directions with velocities 108 km/h and 72 km/h, respectively. If train ‘A’ takes 35s less time than train ‘B’ to cross the tunnel then, length ‘L’ of tunnel is (Given L = 60 l) (1) 1200 m (2) 2700 m (3) 1800 m (4) 900 mRead more on Sarthaks.com - https://www.sarthaks.com/3492985/two-trains-and-length-and-are-travelling-into-tunnel-length-parallel-tracks-from-opposite?
Question Description
Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tunnel of length ‘L’ in parallel tracks from opposite directions with velocities 108 km/h and 72 km/h, respectively. If train ‘A’ takes 35s less time than train ‘B’ to cross the tunnel then, length ‘L’ of tunnel is (Given L = 60 l) (1) 1200 m (2) 2700 m (3) 1800 m (4) 900 mRead more on Sarthaks.com - https://www.sarthaks.com/3492985/two-trains-and-length-and-are-travelling-into-tunnel-length-parallel-tracks-from-opposite? for NEET 2024 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tunnel of length ‘L’ in parallel tracks from opposite directions with velocities 108 km/h and 72 km/h, respectively. If train ‘A’ takes 35s less time than train ‘B’ to cross the tunnel then, length ‘L’ of tunnel is (Given L = 60 l) (1) 1200 m (2) 2700 m (3) 1800 m (4) 900 mRead more on Sarthaks.com - https://www.sarthaks.com/3492985/two-trains-and-length-and-are-travelling-into-tunnel-length-parallel-tracks-from-opposite? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tunnel of length ‘L’ in parallel tracks from opposite directions with velocities 108 km/h and 72 km/h, respectively. If train ‘A’ takes 35s less time than train ‘B’ to cross the tunnel then, length ‘L’ of tunnel is (Given L = 60 l) (1) 1200 m (2) 2700 m (3) 1800 m (4) 900 mRead more on Sarthaks.com - https://www.sarthaks.com/3492985/two-trains-and-length-and-are-travelling-into-tunnel-length-parallel-tracks-from-opposite?.
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