Five coins are tossed once. What is the probability of getting at most four tails ?

This question was previously asked in
NDA 02/2022 Mathematics Official Paper (Held On 04 Sep 2022)
View all NDA Papers >

Answer (Detailed Solution Below)

Option 1 :
Free
NDA 01/2025: English Subject Test
30 Qs. 120 Marks 30 Mins

Detailed Solution

Download Solution PDF

Concept:

If A and B are independent, then P(A and B) = P(A).P(B)

Explanation:

Probability of getting atmost four tails in five tosses = 1 - Probability of getting all five tails

⇒ Probability of getting atmost four tails in five tosses = 1 - P(T,T,T,T,T)

In one toss, P(H) =  and P(T) = 

Since all five tosses are independent,

⇒ P(T,T,T,T,T) =  ×  ×  ×  ×  = 

⇒ Probability of getting atmost four tails in five tosses = 1 - ​​ = ​​​

∴ The correct option is (1).

Latest NDA Updates

Last updated on Jun 18, 2025

->UPSC has extended the UPSC NDA 2 Registration Date till 20th June 2025.

-> A total of 406 vacancies have been announced for NDA 2 Exam 2025.

->The NDA exam date 2025 has been announced. The written examination will be held on 14th September 2025.

-> The selection process for the NDA exam includes a Written Exam and SSB Interview.

-> Candidates who get successful selection under UPSC NDA will get a salary range between Rs. 15,600 to Rs. 39,100. 

-> Candidates must go through the NDA previous year question paper. Attempting the NDA mock test is also essential. 

More Probability of Random Experiments Questions

More Probability Questions

Hot Links: teen patti customer care number online teen patti teen patti joy 51 bonus lotus teen patti