Question

A box contains 20 cards numbered 1-20. You select a card. Without replacing the first card, you select a second card. Find each probability
P(1, then 20)
P(even, then 7)

Answer 1

P(1) = 1/20 and P(20) = 1/19
therefore P(1 and 20) = P(1) * P(20|1) = 1/20 * 1/19 = ....

part b is samething like part a

Answer 2

So the answer would be 1/380

Answer 3

yes, for the 1st one

Answer 4

Ok thank you, would you mind helping me set up the second one please

Answer 5

1-20, how many even numbers are there ?

Answer 6

10

Answer 7

yup, so P(even) = 10/20
and P(7) = 1/19, right ?

Answer 8

YES

Answer 9

Then multiply them together ?

Answer 10

yup

Answer 11

10/380

Answer 12

you got it!

Answer 13

Thanks for your help!!

Answer 14

yoyu're welcome