Tickets numbered 1 to 20 are placed in a hat. Two tickets are drawn out at random, without
replacement. Find the probability that:
a: the first number drawn is even and the second number is odd
b: both of the numbers are prime.
-please help include explanation too, it would be really helpful if u can!-

a. 5/19, b. 14/95

Step-by-step explanation:

a. since the first number drawn has 10/20 chance of being even and it's not put back (you assume that you pull an even #), so the second number pulled has a 10/19 chance of being odd.

10/20*10/19 = 5/19

b. 2, 3, 5, 7, 11, 13, 17, 19 are the prime numbers, so 8/20 for the first pull and then 7/19 for the second pull

8/20*7/19 = 14/95

hello from mrbilldoesmath!

answer:

x - 3

discussion:

x^2 - 9 = (x-3) (x+3)   so

(x^2-9)/ (x + 3) = x-3

you,

mrb