Doubt from kinematics

Ans is not matching please check.

I'm getting C

I think C is the right answer. There might be a mistake on their side...

Don't trust on mypat they fool us on many test papers. Either their question will be wrong or options wrong or even they will mark wrong option as correct answer. When you will see their solution they wouldn't have proper explanation, bla bla.

The ans given is also 'C'. And please explain how you got it coz according to me none of the option is correct

There is no need to solve it. Observe the options, one side there is 's'which is the actual distance between them and on the other side there is the distance covered due to application of brakes with relative velocity of A wrt B.
For no collision or travelling till infinitesimal distance between A and B, 's' must be greater than the distance which it covers when breaks are applied. Which only C shows it. Any further doubt, please ask.

@Samarth_2020 inital relative vel is Va-Vb but final rel vel is -Vb.Therefore the equation v2=u2-2aS won't produce the above result.Tell me where am I wrong?

For minimum distance of approach we won't go till the point where car A stops in ground frame but to the point where car A stops in car B's frame that's why relative velocity at minimum distance of approach is taken to be zero.


Oh thank you very much @Abhishek_2020_5 you cleared my doubt.

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