IBPS SO Prelims Exam Model Paper 9

GIVEN : Probability of getting a pink ball = $\frac{11}{27}$ Number of pink balls = 33 Concept: The probability of any outcome is always less than or equal to one. Formula used: Probability = $\frac{(\text{Number of favorable outcomes})}{(\text{Total number of outcomes})}$ 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’ =$\frac{10x-40}{100 \times 10x}$ ⇒ P(pink) = $\frac{11}{27}$ ∵ P(pink) = No. of pink balls/Total no. of balls Probability of picking a pink ball = $\frac{33}{10x+6x+33}$ ⇒ $\frac{33}{10x+6x+33}$ = $\frac{11}{27}$ ⇒ $\frac{3}{16x+33}$ = $\frac{1}{27}$ ⇒ 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