# A bag contains 4 red and 7 blue balls. What is the probability of drawing a red ball if the first ball drawn is blue? The balls drawn are replaced in the bag.

Category: QuestionsA bag contains 4 red and 7 blue balls. What is the probability of drawing a red ball if the first ball drawn is blue? The balls drawn are 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 red ball if the first ball drawn is blue? The balls drawn are replaced in the bag.

(a) \frac {4}{11}

(b) \frac {8}{11}

(c) \frac {4}{18}

(d) \frac {14}{11}

This question was posed to me during an online interview.

I need to ask this question from Multiplication Theorem on Probability in chapter Probability of Mathematics – Class 12
NCERT Solutions for Subject Clas 12 Math Select the correct answer from above options
Interview Questions and Answers, Database Interview Questions and Answers for Freshers and Experience

Editor">Editor Staff answered 11 months ago

Correct choice is (a)
4
11

The explanation: Total number of balls = 4 + 7 = 11

The probability of the first ball to be blue =
7
11

The probability of drawing red ball as the second ball out without replacement =
4
11