Aakriti was sitting inside train A, which was traveling at 58 km/h, another train B whose length was four times the length of A crossed her in opposite direction in 20 seconds.  If the speed of train B was 68 km/h, then the length of train A (in meters) is?

175 m

Let train A's length = x

Train B's length = 4x

\(\frac{4x}{(58 + 68) × \frac{5}{18}}\) = 20

4x = 20 × 5 × 7 = 700

x = 175 m

[Second train will cross Aakriti, so only second train B's length is considered]