Three unbiased coins are tossed once. Find the probability of getting
(i) exactly 2 tails (ii) exactly one tail (iii) at most 2 tails
(iv) at least 2 tails (v) at most 2 tails or at least 2 heads
Correct Answer - D
`(d)` `P(T)=p`, `P(H)=1-p`
`:.` Required probability
`=P(T or HHT or HHHHT or ….)`
`=p+(1-p)^(2)p+(1-p)^(4)+….`
`=(p)/(1-(1-p)^(2))`
`=(p)/(2p-p^(2))=(2)/(3)`
`impliesp=(1)/(2)`
Correct option is (C) 7/8
If three coins are tossed then possible outcomes are S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT}
\(\therefore\) Total outcomes is n(S) = 8
Let event E...
Correct option is (C) 1
When an unbiased coin is tossed then possible outcomes are S = {H, T}.
\(\therefore\) P(H) = \(\frac12\) & P(T) \(=\frac12\)
\(\therefore\) P(H) + P(T) \(=\frac12+\frac12=1\)
Hence, sum of probabilities of getting a head...