Answer :
We know that
• The probability of a head is 1/2.
,• The probability of a tail is 1/2.
Notice that the number of times they flip a coin is 7. Since both probabilities are the same, we just have to multiply 1/2 seven times by itself.
[tex]P=(\frac{1}{2})^7[/tex]Now, we multiply the probability with 7 since there are 7 possibilities.
[tex]P=7\cdot(\frac{1}{2})^7=7(0.0078125)=0.0546\approx0.055[/tex]Then, we multiply by 100 to express it as a percentage.
[tex]0.055\cdot100=5.5[/tex]