Correct Answer - D
Let Hi
denote the event of getting a head in ith
toss and Ti
denote the event of getting a tail in ith
toss. Then,
Required probability
=P{(H1∩H2∩H3∩H4∩T5∪(T1∩T2∩T3∩T4∩T5)}
=P(H1∩H2∩H3∩H4∩T5)+P(T1∩T2∩T3∩T4∩T5)
=P(H1)P(H2)P(H3)P(H4)P(H5)+P(T1)P(T2)P(T3)P(T4)P(H5)
=(
1
2
)5+(
1
2
)5=
1
16