train starts from station with an acceleration 1m/s^. a boy is 48m behind the train with a constant velocity 10m/s to catch the train.the minimum time after which the boy will catch the train is:

a)4.8s    b)8s     c)10s     d)12s.

give me the solution of this qn.  Answer is b.but my answer is coming both b nd d.

it is very simple -

from given data s= 48m ; u = 10 m/s ; a = 1 m/s^2    t=?

formula

this is a quadratic  equation

 t =  8 s     or     12 s

therefore minimum time from the above answer is  8 seconds then answer is  b

is proof  is correct?

please rate me