IBPS SO Prelims Exam Model Paper 9

GIVEN :
Probability of getting a pink ball =

11

27

Number of pink balls = 33
Concept:
The probability of any outcome is always less than or equal to one.
Formula used:
Probability =

(Number‌of‌favorable‌outcomes)

(Total‌number‌of‌outcomes)

Calculation:
The number of orange balls is 40% less than that of blue balls.
Let the initial no. of blue balls in box be ‘10x’
So, the no. of orange balls in box be ‘6x’ =(

10x–40

100×10x

)
⇒ P(pink) =

11

27

∵ P(pink) = No. of pink balls/Total no. of balls
Probability of picking a pink ball =

33

(10x+6x+33)

⇒

33

(10x+6x+33)

=

11

27

⇒

3

(16x+33)

=

1

27

⇒ 3 × 27 = (16x + 33)
⇒ 81 – 33 = 16x
⇒ 48 = 16x
⇒ x = 3
⇒ No. of blue balls = 10(x) = 10 × 3
⇒ No. of blue balls = 30 balls