Probability of recieving an offer Your friend tells you that he had two job interviews last week. He says that based on how the interviews went, he thinks he has a 20% chance of receiving an offer from each of the companies he interviewed with. Nevertheless, since he interviewed with two companies, he is 50% sure that he will receive at least one offer. Is he right?
My Approach:
since he had 2 interviews, 20% each, the total probability of getting should be 40%?

Hello and welcome to Math.SE.
Your intuition is not serving you correctly here.
If we assume that the events of getting offers from the different companies are independent we find
$$
\begin{align}
\Pr(\text{Friend receives at least 1 offer})
&= 1 - \Pr(\text{Friend receives no offer}) \\
&= 1 - \Pr(\text{No offer from C1 and no offer from C2}) \\
&= 1 - \Pr(\text{No offer from C1}) \cdot \Pr(\text{No offer from C2}) \\
&= 1 - 0.8^2 \\
&= 0.36
\end{align}
$$
Hence the chance of receiving at least one offer would be $36\%$.
