Answer : 4. "8:3"
Explanation :

Answer: D) 8:3 Explanation: Let the speed of the boat upstream be p kmph and that of downstream be q kmph   Time for upstream = 8 hrs 48 min = 845hrs   Time for downstream = 4 hrs   Distance in both the cases is same.   => p x  845= q x 4   => 44p/5 = 4q   => q = 11p/5    Now, the required ratio of Speed of boat : Speed of water current   = q+p2:q-p2   => (11p/5 + p)/2  : (11p/5 - p)/2   => 8 : 3