Question

A sailor goes 8km downstrem in 40minutes and returns in 1hour . Find the speed of the sailor in stil water and the speed of the current

Answer 1

let the speed of sailor in stil water be xkmph
and speed of current be ykmph
a/q
distance =8 km
and time= 0.67hr
and speed of sailor on going downstream =(x+y)kmph
speed =distance /time =8/0.67=11.95kmph ---(1)
and
on going up stream
speed of sailor =(x-y)kmph
distance =8km
time taken =1 hr
speed=distance /time=8/1=8 kmph-------------(2)

Now,
from (1)and(2)
x+y=11.95
and, x-y=8
2x=19.95
x=19.95/2=9.975kmph
and y=11.95-9.975=1. 975kmph

therefore speed of sailor in stil water=9.975kmph
speed of current=1.975kmph

Hope it help you

Answer 2

Answer:

⇒ x + y = 12  

⇒ x - y = 8  

--------------  

⇒ 2x = 20,  

⇒ 2y = 4  

⇒ x = 10,  

⇒ y = 2  

⇒Speed of stream = 2 kmph, Speed of boat = 10 kmph