Question

The odds against a certain event is 5:2 and the odds in favour of another event is 6:5. If both the events are independent, then the probability that at least one of the events will happen is

• A. 50/77
• B. 52/77
• C. 25/88
• D. 63/88

Answer 1

Answer: (B)

52/77

Answer 2

Let A and B be two given events. The odds against A are 5:2, therefore P(1) = 2/7.

The odds in favour of B are 6:5.

Therefore P(2) = 6/11

The required probability

= = 1 - $\left( 1 - \frac { 2 } { 7 } \right) \left( 1 - \frac { 6 } { 11 } \right) = \frac { 52 } { 77 }$