Two brother X and Y appeared for an exam. The probability of selection of X is 1/3 and that of B is 2/7. Find the probability that both of them are selected.
Pick one
A) 2 / 69 B) 2 / 21 C) 2 / 23 D) 2 / 29 E) 2 / 10

Rationale: explanation : let a be the event that x is selected and b is the event that y is selected . p ( a ) = 1 / 3 , p ( b ) = 2 / 7 . let c be the event that both are selected . p ( c ) = p ( a ) ã — p ( b ) as a and b are independent events : = ( 1 / 3 ) ã — ( 2 / 7 ) = 2 / 21 answer : b ) 2 / 21
Answer: B