JEE Advanced2007MathematicsProbabilityActual
Let H₁, H₂, , H_n be mutually exclusive events with P (H_i )>0, i=1,2, , n . Let E be any other event with 0 P (E / H_i ) P (H_i ) for i=1,2, , n . Statement II _ i=1 ^n P (H_i )=1
Options
- AStatement I is true, Statement II is true; Statement II is a correct explanation for Statement I
- BStatement I is true, Statement II is true; Statement II is not a correct explanation for Statement II
- CStatement I is true, Statement II is false
- DStatement I is false, Statement II is true
Correct answer
D. Statement I is false, Statement II is true
Step-by-step solution
Statement : I If P (H_i E )=0 for some i , then P ( H_i E )=P ( E H_i )=0 If P (H_i E ) 0 for i=1,2, . n , then aligned P ( H_i E ) & = P (H_i E ) P (H_i ) P (H_i ) P(E) & .= P ( E H_i ) P (H_i ) P(E) >P ( E H_i ) P (H_i ) [as 0 < P(E) < 1 ] aligned Hence, Statement I may not always be true. Statement II Clearly, H₁ H₂ . H_n=S (sample space) P (H₁ )+P (H₂ )+ +P (H_n )=1 . Hence, Statement II is true.