two parallel rail tracks run north -south. train A moves north with speed 54km/h and train B moves south with speed 90km/h. what is the velocity of a monkey running on roof of a train A against its motion (with velocity of 18km/h with respect to A)as observed by a man standing on ground(in m/s).

let train A move in the north direction and let train B move in the south direction

then v_{A = + 54 km/hr A}

V_B = - 90 km/hr

V_{ma = - 18 km/hr}

_{Vba = Vb - VA = - 90 - 54 = 144KM/HR}

_{Vgb = Vg - Vb = 0 - (-90) = 90 km/hr}

_{Vma = Vm - Va}

_{- 18 = Vm - 54}

_{Vm = -18 +54 = 36 km/hr}

_{Vmg = Vm - Vg = 36 - 0 = 36 km/hr}

_{hope it helps you !!!!!!!!! :)}