Question

A bag contains cards numbered from 1 to 14 one card is drawn at random find the probability of

a.) Selecting a prime number of a multiple of four

b.) selecting a multiple of two or a multiple of three

Answer 1

One: P = 1/2 = 0.5

Two: P = 8/14 = 4/7 = 0.714

Explanation:

One

I take it that the question is a prime number or 4.

P(four) = 1/14

The primes are 2,3,5,7,11,13. There are 6 of them

P(prime) = 6/14

P(prime or four) = 6/14 + 1/14 = 7/14 = 1/2

Two

Multiple of 2 := 2 4 6 8 10 12 14

Multiple of 3 := 9 in addition to 6 and 12 which cannot be counted twice.

P(2 or 3) = 8/14 = 4/7 = 0.714