Two unbiased coins are tossed. What is probability of getting at most one tail ?

A. $\frac{1}{2}$

B. $\frac{1}{3}$

C. $\frac{3}{2}$

D. $\frac{3}{4}$

Correct Answer :

D. $\frac{3}{4}$

Total 4 cases = [HH, TT, TH, HT] Favourable cases = [HH, TH, HT] Please note we need atmost one tail, not atleast one tail. So probability = $\frac{3}{4}$