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IPMAT Indore 2023 - QA (MCQ) Q25 Explanation
December 31, 2024
Explanation:
(c)
Let the fair coin be tossed ‘n’ number of times.
Probability of getting NO heads in ‘n’ successive tosses
=(1/2) x (1/2)……n times = (1/2)^𝑛 = 1/2^𝑛
Probability of getting AT LEAST ONE head = 1- Probability of getting NO heads > 0.8
= 1 - 1/2^n >0.8
= 1 - 0.8 > 1/2^n
= 0.2 > 1/2^n
= 1/5 > 1/2^n
= 5 < 2^𝑛 or 2^𝑛 > 5
So, the minimum value of n that meets the above inequality = 3.