Comprehension

Answer these questions (Qs. 77 - 79) based on the following information.

There are 4 red balls, 4 green balls and 6 blue balls, in a box

If three balls are drawn randomly, what is the probability that one of them is green and the other two are blue?

This question was previously asked in
CSIR-CLRI JSA 2024 Official Paper-I (Held On: 16 Feb, 2025)
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  1. \(\frac{15}{91}\)
  2. \(\frac{24}{91}\)
  3. \(\frac{20}{91}\)
  4. \(\frac{12}{91}\)

Answer (Detailed Solution Below)

Option 1 : \(\frac{15}{91}\)
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Detailed Solution

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Calculation:

Total Number of Balls and Possible Outcomes

Total balls: 4 (red) + 4 (green) + 6 (blue) = 14 balls

We're drawing 3 balls, so the total number of possible combinations is given by the combination formula:

¹⁴C₃ = (14!)/(3! × 11!) = (14 × 13 × 12)/(3 × 2 × 1) = 364

 Favorable Outcomes

We want 1 green ball and 2 blue balls.

Number of ways to choose 1 green ball from 4: ⁴C₁ = 4

Number of ways to choose 2 blue balls from 6: ⁶C₂ = (6 × 5)/(2 × 1) = 15

To get the total number of favorable combinations, we multiply these: 4 × 15 = 60

Calculate the Probability

Probability = (Favorable Outcomes) / (Total Possible Outcomes)

Probability = 60 / 364

Simplify the Fraction

Divide both numerator and denominator by 4: 15/91

Answer:

The probability of drawing one green ball and two blue balls is 15/91.

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