Question

Question 3 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)

Class X1 - Maths -Probability Page 409

Answer 1

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

(a ) total number of outcomes n ( S ) = 6
number of favourable outcomes n(E ) = event getting a number 2 = 3 { there are three faces each with number 2 }
so, P( E ) = n(E )/n(S ) = 3/6 = 1/2

(b) number of favourable outcomes n(E ) = event getting 1 or 3 = 2 + 1 { because there are two faces each with number 1 and one face with number 3}
so, P( E ) = n(E )/n(S ) = 3/6 = 1/2

(c ) number of favourable outcomes n(E ) = event getting a number not 3 = 3 + 2 { because three faces each with number 2 and 2 faces each with number 1 }
so, P(E ) = n(E )/n(S )
= 5/6