How do you work out the odds of something happening?

Question

For example in bingo....

There are 90 numbers and you need to mark off 15 to fill one card. What are the odds of the 15 you need being the first 15 to be called?

Can anyone help and tell me how to do it. Many thanks.

Answer 1

the odds of one of your numbers being called out first is 15/90

the odds of one of the remaining 14 being called out of the 89 that are left is 14/89

the odds of one of the remaining 13 being called from the remaining 88 is 13/88

... get the pattern?

so the answer to your question is that the odds of your 15 numbers being picked out of 90 is:

(15x14x13x12x11x10x9x8x7x6x5x4x3x2x1) in

(90x89x88x87x86x85x84x83x82x81x80

x79x78x77x76)

Answer 2

Millions. The odds on picking 6 numbers from 35 in the natiional lottery are hard enough!