Question

: A store has 15 cars of a certain brand. Among them, 7 are black, 6 are gray and 2 are white. Another store wishes to buy 3 cars of this brand, no matter what color. Let X be the number of sold black cars. Find the probability function of X?

Answer 1

Probability of function ' x ' is
`(1)/(13)`

Explanation:

Store - 1

Total number of car = 15.

The number of

Black car = 7.

Grey car = 6.

White car = 2.

Store -2

The number of car wishes to buy = 3 car.

The number of black car sold = x .

The probability of 'x' = ?.

P ( x ) = P ( first black ) * P ( second black ) * P ( third is black )

P ( x ) =
`(7)/(15) *(6)/(14) *(5)/(13)` =
`(1)/(13)`

So the probability of number of car sold is black or P ( x ) =
`(1)/(13)`