Which of the following statement is correct? I. A boat travels 84 km…
2021
Which of the following statement is correct?
I. A boat travels 84 km downstream and 42 km upstream. If speed of boat and speed of stream are 6 km/hr and 2 km/hr respectively, then total time taken is 20 hours.
II. Length of a platform is 1200 meters. If a 600 meter long train can cross it in 30 seconds, then speed of train is 54 km/hr.
- A.
Only I
- B.
Only II
- C.
Both I and II
- D.
Neither I nor II
Attempted by 20 students.
Show answer & explanation
Correct answer: D
Statement I Verification:
Speed of boat = 6 km/hr, Speed of stream = 2 km/hr.
Downstream speed = 6 + 2 = 8 km/hr. Upstream speed = 6 - 2 = 4 km/hr.
Time taken = (84 / 8) + (42 / 4) = 10.5 + 10.5 = 21 hours.
The statement claims 20 hours, so Statement I is False.
Statement II Verification:
Total distance = Length of train + Length of platform = 600 + 1200 = 1800 meters.
Time = 30 seconds.
Speed (m/s) = Distance / Time = 1800 / 30 = 60 m/s.
Speed (km/hr) = 60 * (18 / 5) = 216 km/hr.
The statement claims 54 km/hr, so Statement II is False.
Final Answer: Option 4 (Neither I nor II)