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

Answer: A) 20% Explanation: Percentage of students passed in English = 60% Percentage of students passed in Hindi = 45% Percentage of students passed in both subjects = 25% ATQ, Percentage of students passed in only English = 60 - 25 = 35% Percentage of students passed in only Hindi = 45 - 25 = 20% Therefore, Percentage of students failed = 100 - (35 + 25 + 20) = 100 - 80 = 20%.

Answer: C) 32 mts Explanation: let 'b' be the Length of bridge from cow to the near end of the bridge and 'a' be the distance of the train from the bridge. 'x' be speed of cow => '4x' speed of trainThen the total length of the bridge 2b + 10.(a-2)/4x = b/x=> a-2 = 4b........(1)Now if it had run in opposite direction(a+2b+10-2)/4x = (b+10-2)/x=> a - 2b = 24......(2)Solving (1) and (2)b = 11 , Therefore length of the bridge is 2 x 11 + 10 = 32mts.