Birthday problem

A friend of mine gave this problem to me. Can someone help me out.

You are sitting in a large waiting room, waiting for a final job interview . In the room with you are a large number of other candidates from all over India. The interviewer says that the first person to be interviewed, who's birthday is today, will be guaranteed a job. But only the first person. It is your birthday today! If it is your father's birthday in one week's time, how many people can be interviewed before you, so that your probability of getting the job falls below 90%?

Please state any assumptions made.

#Probability

Easy Math Editor

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Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$