If two coins are tossed then find the probability of the events : (i) at least one tail turns up (ii) no head turns up (iii) at the most one tail turns up

1. If two coins are tossed then find the probability of the events :

(i) at least one tail turns up

(ii) no head turns up

(iii) at the most one tail turns up 

Sol. When two coins are tossed

S = { HH, HT, TH, TT }

n (S) = 4

(i) Let A be the event that atleast one tail turns up

A = { HT, TH, TT }

n (A) = 3

P (A) = n(A)/n(S)

∴ P(A) = 3/4

(ii) Let B be event that no head turns up

B = { TT }

n (B) = 1

P(B) = n(A)/n(S)

∴ P(B) = 1/4

(iii)Let C be the event that at the most one tail turns up

C = { HH, HT, TH }

n (C) = 3

P (C) = n(C)/n(S)

∴  P (C) = 3/4