you have a bag with tiles numbered 1-12. what is the probability that a tile you choose at random is an odd number or a prime number

Question

a. 5/12

b. 7/12

c. 2/3

d. 1/2

Answer 1

For Odd number : n(O) = {1,3,5,7,9,11 } => 6

For Prime number : n(P) = { 2,5,7,11 } => 4

But ,as { 5,7,11 } are both prime and odd numbers, they have to be removed from n(P), So n (P) = 1 { which is 2 }

n(S) = 12 { Total sample space }

The probability of Odd number or prime number = n(O)/n(S) + n(P)/n(S)

= 6/12 + 1/12

= 7/12