linear equation

Let the speed of A and B be V_A and V_B respectively.

V_A = V_B - 4        .....(1)

Now in the same amount of time B reaches Meerut, i.e. covers 60 km and returns back i.e. 12 km. and let this time be T. But A travels only 60 - 12 = 48 km in the same time T.

Hence,

V_A T = 48         ....(2)

V_BT = 60+12 = 72

(V_A + 4)T = 72      ... from (1)

V_AT + 4T = 72    

48 + 4T = 72     ... from (2)

T = 6 hrs.

V_AT = 48

V_A = 48/T = 48/6 = 8 km/hr.

Regards,

Team,

TopperLearning.