A boat takes total 10 hr. to cover 102 km in downstream and 63 km in upstream. The time spent to cover 34 km in downstream is equal to the time taken to cover 24 km in still water. Speed of boat in upstream is how much greater than the speed of current?

3 km/hr

Let speed of boat = U km/hr, 

Speed of water = V km/hr

Speed of boad in Downstream (D.S.) = U + V

Speed of boad in Upstream (U.S.) = U - V

ATQ,

                     (U+V)  :    (U)

Distance →      34     :    24   

                        17    :    12

Speed    →       17    :    12                 (Distance ∝ Speed)

Here,

(U + V) = 17R, U = 12R ⇒ V = 5R and

(U - V) = 7R

Now,

⇒ \(\frac{102}{17R}\) + \(\frac{63}{7R}\) = 10

⇒ \(\frac{6}{R}\) + \(\frac{9}{R}\) = 10

⇒ \(\frac{15}{10}\) = R

⇒ R = \(\frac{3}{2}\)

Speed of boat upstream - speed of current = (U-V) - V = U - 2V = 12R - 10R = 2R = 2 ×\(\frac{3}{2}\) = 3 km/hr