The minimum number of times one has to toss a fair coin so that the probability of observing at least one head is at least 90 % is:

Question

The minimum number of times one has to toss a fair coin so that the probability of observing at least one head is at least 90 % is:, 2, 4, 5, 3

MARKS App · Accepted Answer

Let a fair coin is tossed n times, then P ( at least one head ) = 1 – P ( all tails ) = 1 – 1 2 n > 90 100 (given) ⇒ 1 2 n 1 - 90 100 = 1 10 ⇒ 2 n > 10 ⇒ n ≥ 4

Search any question & find its solution

Looking for more such questions to practice?