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 
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1 Answers
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