Question

a takes 3 hours more than B to walk 30 km full stop but if a double space he is ahead of B by 1.5 hours find their speed of walking

Answer 1

Let the speed of A and B be x km/hr and ykm/hr respectively.

We know that,



Given, time taken by A =  time taken by B + 3 hr

∴ Time taken by A – 3 hr = Time taken by B



Solving (1) and (2), we get



Putting the value of y in equation (1), we get



Thus, the speed of A is and speed of B is 5 km/hr.

Cheers!

Answer 2

Let the speed of a be Va and speed of B be Vb.
And time taken by B to comp. 30 km be t
Then
Vb=30/t          ...........(1)
Va=30/t+3      ...........(2)
on dividing (1) by (2) we get
Vb/Va=3+t/t  ....................(a)

now, as given in ques.
2Va=30/t-1.5    ................(3)
divide eqn. (1) by (3)
Vb/Va=2(t-1.5/t)    .............(b)

on putting rhs equal of eqns. (a) & (b) we get 
t=6hrs.

Thus Vb=5km/hr
          Va=3.34km/hr.