Statistics And Probability Question 253
Question: Out of 40 consecutive natural numbers, two are chosen at random. Probability that the sum of the numbers is odd, is
[MP PET 1997; Pb. CET 2000]
Options:
A) $ \frac{14}{29} $
B) $ \frac{20}{39} $
C) $ \frac{1}{2} $
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
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Required probability $ =\frac{{}^{20}C_1\times {}^{20}C_1}{{}^{40}C_2}=\frac{20\times 20\times 2}{40\times 39}=\frac{20}{39}. $