The ratio of the speeds of a motor boat and that of the current of water is 26 : 4. The boat goes certain distance against the current in 6 hrs. The time taken by the boat to come back is ______

4 hrs 24 minutes

The correct answer is Option (2) → 4 hrs 24 minutes **

Speed of motor boat : speed of current = $26:4$

Let boat speed in still water = $26k$

Let current speed = $4k$

Upstream speed = $26k - 4k = 22k$

Downstream speed = $26k + 4k = 30k$

Let the distance be $d$.

Upstream time is given: $6$ hours

$\displaystyle \frac{d}{22k} = 6 \quad\Rightarrow\quad d = 132k$

Downstream time:

$\displaystyle \text{Time} = \frac{d}{30k} = \frac{132k}{30k} = \frac{132}{30} = 4.4$

Time taken to come back = 4.4 hours= 4 hrs 24 minutes