In a lottery where you need to hit 6 numbers out of 45, the probability of winning is 1 out of 8145060. I also how to calculate the probability to hit, say, 5 out of the 6 numbers (among the 45).
But I have doubts on how to calculate the probability of hitting 5 numbers plus an extra one. This is, I have guess only 5 out of 6 and no one got the winning combination, so a bonus number is taken out for a consolation prize. And that number should be my missed 6th.
I thought that, in this case, you were hitting 6 out of 7 numbers taken from 45, but I got a probability of 6/45379620, which it's pretty much the same as hitting the winning combination, and I don't think this could be right.
According to the answer key, I should get 8/2036265 (about 25 times higher, which sounds reasonable).
I will appreciatte your kind helping me to solve this problem. Thank you.