Q. The odds against a certain event are 5 :2 and the odds in favour of another independent event are 6 : 5. The probability that at least one of the events will happen, is
A) $\frac{25}{77}$
B) $\frac{52}{77}$
C) $\frac{12}{77}$
D) $\frac{65}{77}$
Explanation
(b)
Let $A$ and $B$ are two events
$\therefore\ P(A) = \frac{2}{7},P(B) = \frac{6}{11}$
$\therefore$Required probability$= 1 - P\left( \overline{A} \right)P(\overline{B})$
$= 1 - \left( 1 - \frac{2}{7} \right)\left( 1 - \frac{6}{11} \right)$
$= \frac{52}{77}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.