Question

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!-

Answer 1

Answer: 5/19

Explanation:

There is a total of 20 tickets numbered from 1 to 20.

10 of the tickets has even number and 10 of the tickets have odd numbers.

probability of drawing a ticket that has even number =10/20 which is equal to 1/2

there are total 19 tickets and 10 odd tickets are available.

Probability of drawing a ticket that has odd number =1019

probability =1/2∗10/19=5/19

Answer 2

a. 5/19, b. 14/95

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