Question

Batman really wants to move out of his cheap apartment. He buys some lottery tickets from the local 7-11. The probability of winning on a ticket is 1 in 10.

a) What is the probability Batman will win on his second ticket?
b) What is the probability he will win on his first four tickets?
c) What is the expected number of tickets Batman would have to buy before winning?

Answer 1

@Hero @Mertsj @myininaya

Answer 2

c) if his chances are winning are one in ten, he expects to buy 10

Answer 3

These are known as independent events.
a)1/10
b)\(\Large \color{MidnightBlue}{\Rightarrow ({1 \over 4})^4 }\)

c) as Mr. Satellite said.

Answer 4

You just have to multiply the probabilities in these cases.

Answer 5

I'm not sure about (a)

Answer 6

b) probability he wins on four tickets depends on whether the question means wins on all four, or one out of the four
all four is what parth said \((.1)^{4}\) but if it means once in the four that is something different

Answer 7

Oops I got confused.

Answer 8

\(\Large \color{MidnightBlue}{\Rightarrow ({1 \over 10})^4 }\)

Answer 9

Hey, how did you get that answer, Parth?

Answer 10

@ParthKohli

Answer 11

As I said, we multiply the probabilities.

Answer 12

Oh, ok. Thank you all!