The speed of the boat in still water is 5 times that of current, it takes 1.1 hour to row to point B from point A downstream. The distance between point A and point B is 26.4 km. How much distance (in km) will it cover in 330 minutes upstream?

Let the speed of the current be x kmph
Then speed of the boat in still water = 5x
∴Downstream speed = (5x + x) = 6x kmph
Upstream speed = (5x - x) = 4x kmph


According to question,
1.1 × 6x = 26.4
⇒6.6x =26.4
⇒x =26.4/6.6
∴x = 4kmph
∴Upstream speed = 4x = 4 × 4 = 16 kmph

330 minutes = 5(1/2) hours = 11/2 hours

∴Required distance travelled upstream = Speed × Time
= 16 × (11/2) hours
= 88 km