A steamer, going downstream in a river, covers the distance between two towns in 20 hours . Coming back upstream , it covers this distance in 25 hours . The speed of water is 4km/hr . Find the distance between the two towns.
Answers
Answer : 800 kms.
Step by step explanation :
Let the speed of boat be 'x' km/hrs.
Let the distance between two towns be 'y' kms.
Speed of the boat upstream = ( x - 4 ) km/hrs.
Speed of the boat downstream = ( x + 4 ) km/hrs.
As per your question,
y/(x + 4) = 20
.°. y = 20(x + 4).. (1)
Now,
Given next,
y/(x - 4) = 25
.°. y = 25 (x - 4).. (2)
Comparing eq. (1) and (2)
20 (x + 4) = 25 (x - 4)
20x + 80 = 25x - 100
180 = 5x
36 = x
Putting value of x in eq (1)
y = 20(x + 4)
y = 20( 36 + 4)
y = 20 × 40
y = 800 km
Thus,
We got the value of y as 800 km.
Thus, distance between the two towns is 800 km.
Step-by-step explanation:
Speed of the water=4km/hr
Speed of the steamer = x km/hr
Distance covered downstream =
Speed ×Time=(4+x km/hr)× 20 hours=20(4+x) km=80+20x
Distance covered upstream
=Speed×Time
={(x-4)km/hr} ×25 hours
=25x-100 km
80+20x=25x-100
20x-25x=-100-80
-5x=-180
x=-180÷-5x=36 km/hr
Distance between two towns=
80+20x=80+20×36
=80+720=800 km