Subject
Quantitative Aptitude
Topic
Probability
In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:
In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:
ক)
21/46খ)
25/117গ)
1/50ঘ)
3/25Explanation
Let S be the sample space and E be the event of selecting 1 girl and 2 boys. Then, n(S) = Number ways of selecting 3 students out of 25 = 25C3 =(25 x 24 x 23)/ (3 x 2 x 1) = 2300. n(E) = (10C1 x 15C2) = {10 x (15 x 14)/(2 x 1) = 1050. P(E) = n(E)/n(S) =1050/2300 = 21/46 16. Two dice are thrown simultaneously. What is the probability of getting two numbers whose product is even? ( A ) 1/2 ( B ) 3/4 ( C ) 3/8 ( D ) 5/16 In a simultaneous throw of two dice, we have n(S) = (6 x 6) = 36. Then, E = {(1, 2), (1, 4), (1, 6), (2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6), (3, 2), (3, 4),(3, 6), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6), (5, 2), (5, 4), (5, 6), (6, 1),(6, 2), (6, 3), (6, 4), (6, 5), (6, 6)} So, n(E) = 27. Therefore, P(E) = n(E)/ n(S) = 27/36 = ¾.Related questions
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