question_answer

In a certain population 10% of the people are rich, 5% are famous and 3% are rich and famous. The probability that a person picked at random  from  the population is either famous or rich but not both, is equal to           [UPSEAT 2004]

A)                 0. 07      

B)                 0.08       

C)                 0. 09      

D)                 0. 12

Correct Answer: C

Solution :

                   Here, \[P(R)=\frac{10}{100}=0.1\], \[P(F)=\frac{5}{100}=0.05\]                    \[P(F\cap R)=\frac{3}{100}=0.03\]                    \ Required probability = \[P(R)+P(F)-2P(F\cap R)\]                                                                           = 0.1 + 0.05 ? 2(0.03) = 0.09.