Please Help ???

Question

A Number Is Chosen At Random From 1 To 25. Find The Probability Of Selecting An Even Number Or A Multiple Of 3.

 

Please Explain All Steps.... C:

Answer 1

Let A be the event of selecting an even number

Let B be the event of selecting a multiple of 3 

 

In general, P(A OR B) = P(A) + P(B) - P(A AND B) 

 

There are 12 even numbers from 1 to 25 so P(A) = 12/25 

There are 8 multiples of 3 from 1 to 25 so P(B) = 8/25 

There are 4 numbers that are both even and a multiple of 3 from 1 to 25 so P(A AND B) = 4/25 

 

So P(A OR B) = 12/25 + 8/25 - 4/25 = 16/25 = 0.64