Question

A die has two faces each with number ‘1’, three faces each with number ‘2’ and one face with number ‘3’. If die is rolled once, determine (i) P(2) (ii) P(1 or 3) (iii) P(not 3)

Answer 1

A die has two faces each with number 1, three faces each with number 2and one face with number 3.

The total number of faces is 6.

(i)

The number of faces with number 2 is 3.

The probability P( 2 ) is calculated as follows,

P( 2 )= 3 6 = 1 2

(ii)

The probability P( 1or3 ) is calculated as follows,

P( 1 or 3 )=P ( 2 ) ′ =1−P( 2 ) =1− 1 2 P( 1 or 3 )= 1 2

(iii)

The number of faces with number 3is 1.

The probability P( 3 )is calculated as follows,

P( 3 )= 1 6

The probability P( not3 ) is calculated as follows,

P( not3 )=1−P( 3 ) =1− 1 6 P( not3 )= 5 6