Class 11 Maths Chapter 14: Probability MCQs with answers
10 multiple-choice questions on Probability, each with its answer and the reason, written from the NCERT chapter. For school exams on the CBSE pattern and JEE Main, which are set from the same NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter.
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Answer: (a) 8
S = {1, 2, ..., 8} has 8 sample points, and each singleton is a simple event, so there are exactly 8 simple events.
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Answer: (c) the ball is neither green nor white
No outcome is neither green nor white, so that event is the empty set φ. 'Green or white' is the whole sample space, the sure event.
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Answer: (b) {3, 6}
A = {3, 6, 9, 12} and B = {9, 10, 11, 12}. A – B = A ∩ B′ keeps the elements of A not in B: {3, 6}.
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Answer: (d) E: the number is a perfect square; F: the number ends in 7
No perfect square ends in 7 (squares end in 0, 1, 4, 5, 6 or 9), so E ∩ F = φ. The others share 10, 11 and 99 respectively.
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Answer: (b) 16
April has 30 equally likely dates; the Sundays are the 1st, 8th, 15th, 22nd and 29th. P = 5/30 = 1/6.
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Answer: (a) 14
P(A) + P(A′) = 1 gives P(A) + 3P(A) = 1, so P(A) = 1/4.
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Answer: (d) 0.25
The probabilities of all the outcomes add to 1: P(ω₃) = 1 – 0.3 – 0.45 = 0.25.
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Answer: (c) 35
k + 2k + 3k + 4k = 1 gives k = 1/10. P({ω₂, ω₄}) = 2k + 4k = 6/10 = 3/5.
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Answer: (a) 47
P(k) = ck with c(1 + 2 + ... + 6) = 21c = 1, so c = 1/21. P(even) = (2 + 4 + 6)/21 = 12/21 = 4/7.
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Answer: (b) 0.17
The two events are mutually exclusive, so P(cooker or mixer) = 0.05 + 0.12 = 0.17.