Answer:
Number of trails required equals 8.
Explanation:
The probability that all three coins have heads as their result equals
[tex]P(E)=P(1)\times P(2)\times P(3)\\\\P(E)=1/2\times 1/2\times 1/2\\\\ \therefore P(E)=\frac{1}{8}[/tex]
Now using basic theorem of Geometric probability we have
"If probability of success is p in every trial, then expected number of trials until success is 1/p"
Thus the no of trails until success equals [tex]\frac{1}{\frac{1}{8}}=8[/tex]
