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A box contains 3 red pencils, 2 blue pencils and 4 green pencils.
Raj chooses 2 pencils at random, without replacement.
Calculate the probability that
(a) they are both red
(b) they are both the same colour
(c) exactly one of the two pencils is green.
Thankyou
Answers
Answer:
(a) Probability of choosing both red pencils =1/12*
(b) Probability of choosing two pencils of the same colour = 7/36
(c) Probability of choosing exactly one green pencil = 1/3 + 4/9 = 7/18
Step-by-step explanation:
Total number of pencils = 3 + 2 + 4 = 9
(a) Probability of choosing a red pencil on the first draw = 3/9
Probability of choosing another red pencil on the second draw (without replacement) = 2/8 = 1/4 (since one red pencil has already been chosen)
Probability of choosing both red pencils = (3/9) x (1/4) = 3/36 = 1/12
(b) Probability of choosing two pencils of the same colour = Probability of choosing two red pencils + Probability of choosing two blue pencils + Probability of choosing two green pencils
Probability of choosing two red pencils = 3/9 x 2/8 = 1/12
Probability of choosing two blue pencils = 2/9 x 1/8 = 1/36
Probability of choosing two green pencils = 4/9 x 3/8 = 1/6
Probability of choosing two pencils of the same colour = 1/12 + 1/36 + 1/6 = 7/36
(c) Probability of choosing exactly one green pencil = Probability of choosing one green and one non-green pencil (i.e., red or blue) + Probability of choosing one non-green (i.e., red or blue) and one green pencil
Probability of choosing one green and one non-green pencil = (4/9) x (6/8) x 2 = 12/36 = 1/3 (since there are two ways to choose one green and one non-green pencil)
Probability of choosing one non-green and one green pencil = (6/9) x (4/8) x 2 = 4/9
Probability of choosing exactly one green pencil = 1/3 + 4/9 = 7/18*
To know more about probability refer:
https://brainly.in/question/20798570
https://brainly.in/question/54143022
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