RBI Assistant Model Paper 8

Let speed of the boat in still water and speed of the current be x km/hr and y km/hr respectively.
ATQ

30

x−y

+

45

x+y

= 13 .......... (i)

24

x−y

+

30

x+y

= 10 .......... (ii)
By equating (i) and (ii)

300

x−y

+

450

x+y

=

312

x−y

+

390

x+y

60

x+y

=

12

x−y

x

y

=

3

2

Let x = 3a and y = 2a
Now,

30

3a−2a

+

45

3a+2a

= 13

30

a

+

45

5a

= 13
a = 3
∴ speed of the current = 6 km/hr