Question

2.
A boat goes 14 km upstream in 56 minutes. The
speed of stream is 2 km/hr. The speed of boat in
still water is
(a) 6 km/hr
(b) 15 km/hr
(c) 14 km/hr
(d) 17 km/hr
(e) None of these​

Answer 1

(b) 15 km/hr

is the correct option.....

Answer 2

Step-by-step explanation:

let the speed of the stream be x kmph.

speed of stream is 2 kmph

distance = 14km

time taken is 56min = 56 ÷ 60 = 14

                                                     15      

as time  = distance  = 14

                 speed        x-2              (while going upstream we have to subtract the speed of stream from the speed of boat)

∴ 14   = 14         ∴ 1  =   1

  15        x-2          15    x-2

by cross multiplying

x-2 = 15

x = 15 + 2

x = 17 kmph  (option d)