Question

A spinner has equal regions numbered 1 through 15. What is the probability that the spinner will stop on an even number or a multiple of 3?

Answer 1

Answer:

Given spinner has equal regions numbered from 1 to 15.

Even number regions are (2,4,6,8,10,12,14) that is total 7 even regions. ==> p(A) = 7/15

Regions that are multiple of 3 are (3,6,9,12,15) that is total 5 regions. ==>p(B) = 5/15

common regions in both are (6,12) that is 2 regions. ==> p(A intersection B) = 2/15

Now the probability that the spinner will stop on an even number or a multiple of a is:

p(A union B) = p(A) + p(B) - p(A intersection B)

= 7/15 + 5/15 - 2/15

= 10/15

= 2/3

= 0.6666