# A bag contains 4 red and 7 blue balls. What is the probability of drawing a blue ball if the first ball drawn is red? The balls drawn are not replaced in the bag.

Category: QuestionsA bag contains 4 red and 7 blue balls. What is the probability of drawing a blue ball if the first ball drawn is red? The balls drawn are not replaced in the bag.
Editor">Editor Staff asked 11 months ago

A bag contains 4 red and 7 blue balls. What is the probability of drawing a blue ball if the first ball drawn is red? The balls drawn are not replaced in the bag.

(a) \frac {7}{10}

(b) \frac {8}{10}

(c) \frac {7}{1}

(d) \frac {4}{11}

I have been asked this question during an online exam.

This interesting question is from Multiplication Theorem on Probability topic in division Probability of Mathematics – Class 12
NCERT Solutions for Subject Clas 12 Math Select the correct answer from above options
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Editor">Editor Staff answered 11 months ago

The correct option is (a)
7
10

To explain I would say: Total number of balls = 4 + 7 = 11

The probability of the first ball to be red =
4
11

The probability of drawing blue ball as the second ball out without replacement =
7
10