Anumber from 1 to 100, inclusive, is selected at random. what is the probability that the
number selected—
a. is a prime number?
b. contains the digit 9?
c. is both prime and contains the digit 9?

A : 1/4

B : 19/100

C : 3/50

Step-by-step explanation:

There are 25 prime numbers from 1 to 100.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97.

25/100 = 1/4

There are 19 numbers that contain 9.

9, 19, 29, 39, 49, 59, 69, 79, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, and 99.

19/100

There are 6 numbers that are prime and contain 9.

19, 29, 59, 79, 89, 97.

6/100 = 3/50

answer: .64

step-by-step explanation

set up the formula for standard deviation for this set of numbers, then simplify