IBPS SO Prelims Exam Model Paper 2

Given:
Boat can travel a certain distance upstream and downstream in 15 hours and 8 hours respectively
Time taken to travel 7500 km downstream is 10 hours
Formula:
In case of upstream, time =

distance

(x−y)

In case of upstream, time =

distance

(x+y)

Calculation:
Let the speed of the boat be x km/hr and the speed of the stream be y km/hr
Let d be the distance covered
⇒

d

(x−y)

= 15
⇒

d

(x+y)

= 8 ----(1)
Now,
Time taken to travel 7500 km downstream is 10 hours

7500

(x+y)

= 10
⇒ x + y = 750 ----(2)
Putting the value of (x + y) in equation (1), we get
⇒ d = 8 × 750 = 6000
⇒

d

(x−y)

= 15
⇒

6000

(x−y)

= 15
⇒ x – y = 400 ---3
Solving equation (2) and (3), we get
⇒ x = 575 and y = 175
∴ Speed of the stream is 175 km/hr