A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?
Choose the correct answer
A) 5 : 6	B) 6 : 5	C) 8 : 3	D) 3 : 8	E) None of these
Explanation :   Let the rate upstream of the boat = x kmph   and the rate downstream of the boat = y kmph   Distance travelled upstream in 8 hrs 48 min = Distance travelled downstream in 4 hrs.   Since distance = speed × time, we have   x × (8(4/5)) = y × 4   x × 44/5 = y × 4   x × 11/5 = y --------- (equation 1)   Now consider the formula given below   Hence, speed of the boat = (y+x)/2   speed of the water = (y−x)/2   Required Ratio = left(fracy+x2right):left(fracy−x2right)left(fracy+x2right):left(fracy−x2right)   = (y + x):(y − x)   ∵ (Substituted the value of y from equation 1)   = left(frac11x5+xright):left(frac11x5−xright)left(frac11x5+xright):left(frac11x5−xright)   = (11x + 5x) : (11x − 5x)   = 16x : 6x   = 8 : 3 Answer : Option 8 : 3
<result>C</result>
A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?