Train A started from Kanpur station and at the same time train B started from Agra station toward each other. After crossing each other they take 4 hours and 36 hours respectively to reach the destination (i.e. Start point of other train). If the speed of train A is 180 km/h, then find the speed of train B.
Answer
Correct Answer : b ) 60 km/h
Explanation :According to the question
We know that,
\({s1 \over s2}=\sqrt{T_2 \over T_1}\)
Where, s1 = speed of train A and s2 = Speed of train B and T1 be the time taken by train A after crossing and T2 be the time taken by the train B after crossing.
T1 = 4hrs and T2 = 36hrs
\(s1 \over s2\)=\(\sqrt{36 \over 4}\) ⇒\(\sqrt 9\)
\(s_1\over s_2\)=\(3 \over 1\)
Speed of train A = 180km/h
3unit = 180 km/h
1 unit = 60 km/h
Speed of train B = 60km/h
Hence, (b) is the correct answer.
Comments