Question

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?

• A. 2 : 1
• B. 3 : 2
• C. 8 : 3
• D. Cannot be determined
• E. None of these

Answer 1

Answer: (C)

The correct option is C 8 : 3
Let the man's rate upstream be x kmph and that downstream be y kmph.
Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.
$\to (x\times 8\frac{4}{5})=(y\times 4)$
$\to \frac{44}{4}x=4y$
$\to y=\frac{11}{5}x$
$\to$ Required ratio $=\left(\frac{y+x}{2}\right):\left(\frac{y-x}{2}\right)$
$=(\frac{16x}{5}\times \frac{1}{2}):(\frac{6x}{5}\times \frac{1}{2})$
$=\frac{8}{5}:\frac{3}{5}$
$=8:3$