**Question **: An unbiased coin is tossed 6 times. The probability that third head appears on the sixth trial is

(A) 5/16

(B) 5/32

(C) 5/8

(D) 5/64

**Answer **: option (B)

**Solution **:

Probability of getting 2 heads in the first 5 trials is

5C_{2}\left( \dfrac{1}{2}\right) ^{2}\left( \dfrac{1}{2}\right) ^{3}=\dfrac{10}{32}=\dfrac{5}{16}Therefore, the probability that third head appears on the sixth trial is 5/16×1/2=5/32.