Question

Rooms in a hotel are numbered from 1 to 19.

Rooms are allocated at random as guests arrive.
(a) What is the probability that the first guest to arrive is given a room which is a prime number?
(1 is not a prime number.)

(b) The first guest to arrive is given a room which is a prime number.
What is the probability that the second guest to arrive is given a room which is a prime number?​

Answer 1

a) 8/19 chance

b) 7/19 chance (I'm not 100% sure)

Explanation:

A) since there are 8 prime numbers from 1-19 we can say that the probability is 8 over 19 or 8/19