If the taken by boat to travel upstream on Monday is `(45)/(11)` hrs. more than the time taken by it to travel downstream on the day, then find the speed of boat in still water on Monday ?

Options

A. 22 kmph
B. 18 kmph
C. 20 kmph
D. 19 kmph

Answer

C

Explanation

Let speed of boat in still water on Monday =x
According to question.
`(15xx18)/(x-2) =(45)/(11)+(15+15)/(x+2)`
`15((18)/(x-2)-(16)/(x+2))=(45)/(11)`
`(18)/(x-2)-(16)/(x+2)=(3)/(11)`
If we put x =20
Then it satisfy the above equation
`:. x=20` kmph