IBPS PO Prelims Model Paper 11

Speed of boat in still water = x kmph.
Speed of current = y kmph.
Rate downstream = (x + y) kmph
Rate upstream = (x – y) kmph.
According to the question,
x+y=

20

1 40 60

kmph
⇒x+y=

20

5 3

=

20×3

5

= 12 kmph ....(i)
∴

2×20

x+y

=

20

x−y

⇒ 2x – 2y = x + y
⇒ x = 3y .....(ii)
From equation (i),
3y + y = 12
⇒ 4y = 12 ⇒ y =

12

4

= 3 kmph
∴ x = 3 × 3 = 9 kmph
∴ Rate upstream = (x – y) kmph = 9 – 3 = 6 kmph