Question

Balls numbered from 1 to 38 are placed in a contianer and stirred. If one is drawn at random what is the probability that the number is a prime number?

Answer 1

`\text{Probability}=(6)/(19)`

Explanation:

Given : Balls numbered from 1 to 38 are placed in a container and stirred. If one is drawn at random.

To find : The probability that the number is a prime number

Solution :

Probability is defined by,

`\text{Probability}=\frac{\text{Favorable outcome}}{\text{Total number of outcome}}`

Favorable outcomes - To get the number is prime number from 1 to 38

Prime numbers are those which were not divisble by any number except 1 and itself.

From 1 to 38 - 2,3,5,7,11,13,17,19,23,29,31,37

Favorable outcome = 12

Total number of outcome is 1 to 38 = 38

`\text{Probability}=\frac{\text{Favorable outcome}}{\text{Total number of outcome}}`

`\text{Probability}=(12)/(38)`

`\text{Probability}=(6)/(19)`

Answer 2

The primes in the range 1–38 are ...

... 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37

There are 12 of them, so the probability of drawing a prime is

... 12/38 = 6/19