A boat goes 1 km downstream in 7\(\frac{1}{2}\) minutes and goes 5 km against the stream in one hour. Find the velocity of the boat in still water.

12\(\frac{1}{2}\) 6\(\frac{1}{2}\) 3\(\frac{1}{2}\) 6 km/hr

6\(\frac{1}{2}\)

ATQ, (D.S)  Downstream speed = \(\frac{1}{7\frac{1}{2}}\) x 60 = 8 km/hr (U.S)  Upstream speed = \(\frac{5}{1}\) = 5 km/hr Velocity of boat = \(\frac{D.S + U.S}{2}\) = \(\frac{8 + 5}{2}\) = 6\(\frac{1}{2}\) km/hr