Three integers are chosen at random from the first 20 integers. The probability that their product is even is

Question : Three integers are chosen at random from the first 20 integers. The probability that their product is even is

(A) 2/19

(B) 3/29

(C) 17/19

(D) 4/29

Answer : option

Solution :

The total number of ways in which 3 integers can be chosen from first 20 integers is 20C_{3}. The product of three integers will be even if at least of the integers is even.

Therefore, the required probability is,

= 1 – probability that none of the three integers is even

= 1-\dfrac{10C_{3}}{20C_{3}}=1-\dfrac{2}{19}=\dfrac{17}{19}

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