Question

People of a village randomly tell the truth and tell a lie, nothing is certain.
Suppose, one day you visit the village and ask a person what day it is. He answers,
“Sunday”. What’s the probability of the day actually being Sunday?

Answer 1

People of a village randomly tell the truth and tell a lie, nothing is certain. Suppose, one day you visit the village and ask a person what day it is. He answers, "Sunday". What's the probability of the day actually being Sunday?

Solution

There are seven variants to say what day it is: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday and Saturday. People of a village randomly tell the truth and tell a lie, that's why the probability of the day actually being Sunday is

$$P = \frac {1}{7}.$$

Answer: $\frac{1}{7}$