Three students A,B,C solve a problem. Probabilities 1/2, 2/3, 3/4. Probability that exactly two of them solve it is: MCQ with Answer and Explanation

Three students A,B,C solve a problem. Probabilities 1/2, 2/3, 3/4. Probability that exactly two of them solve it is:
A. 7/24
B. 13/24
C. 1/4
D. 11/24
Answer: Option D
Solution (By JKSSB Mock Tests)
P(AB'C) = 1/2 * 1/3 * 3/4 = 3/24; P(AB'C)? Let's compute exactly two: A and B not C: 1/2*2/3*1/4=2/24; A not B C: 1/2*1/3*3/4=3/24; not A B C: 1/2*2/3*3/4=6/24. Sum = 11/24.

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Practice More Statistics Questions

Question #1
TFR of 2.1 children per woman is called replacement-level fertility because it:
A. Results in zero population growth in the long run
B. Ensures population decline
C. Doubles population
D. Equals NRR=1 exactly

Correct Answer: Option A


Explanation:
TFR of about 2.1 ensures each generation exactly replaces itself (assuming low mortality), leading to eventual zero growth.

This question belongs to: Accountancy and Statistics Statistics
Question #2
Fisher's Ideal Index Number is the:
A. Harmonic mean of Laspeyres and Paasche index numbers
B. Geometric mean of Laspeyres and Paasche index numbers
C. Arithmetic mean of Laspeyres and Paasche index numbers
D. Median of Laspeyres and Paasche index numbers

Correct Answer: Option B


Explanation:
Fisher's index is calculated as the geometric mean of Laspeyres and Paasche indices, balancing their upward and downward biases.

This question belongs to: Accountancy and Statistics Statistics
Question #3
A box contains 4 white and 6 black balls. A ball is drawn and not replaced. Then another ball is drawn. The probability that both are white is:
A. 1/6
B. 2/15
C. 12/90
D. 6/90

Correct Answer: Option B


Explanation:
(4/10)×(3/9)=12/90=2/15.

This question belongs to: Accountancy and Statistics Statistics