Question

#Aptitude.

Answer 1

D(AB)=D(BA)= 2500 ml
T(AB) + T(BA) = 8x60 +20 = 500 minutes = 3000 seconds

To find: S(AB)

Outbound Speed = S(B to A) = S(BA)
(S(BA) + S(AB)) / 2 = ((100+20) /100) x S(BA)

On Solving,
S(AB) = 1.4 x S(BA)

Since speed =Distance / Time,
T(BA) = 1.4 x T(AB)    …..(Inversely proportional to speed)
Adding T(AB) on Both Sides,
T(AB) + T(BA)  = 2.4 x T(AB)
3000  =  2.4 x T(AB)
T(AB) = 1250 seconds

Therefore, S(AB) = D(AB)/T(AB) = 2500ml / 1250 sec = 2 ml/sec