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(#M40040020) ELITMUS Category question Keep an EYE

Out of 40 consecutive integers, two are chosen at random. Find the probability that their sum is even?

Asked In Elitmus Dada Khalandar (10 years ago)

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Read Solution (6) :

sravani  (10 years ago)

(20c2+20c2)/40c2=19/39

Is this solution Helpfull? Yes (7) | No   

aman gupta  (10 years ago)

even+even=even
odd+odd=even
40 consecutive integer will have 20 even and 20 odd numbers.
20/40*19/39+20/40*19/39

Is this solution Helpfull? Yes (7) | No (1)  

khushboo goenka  (10 years ago)

19/39
either to choose 2 odd no or 2 even thn sum will b even
20c2+20c2/40c2

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Akash kumar  (10 years ago)

Forty consecutive integers will have 20 even and 20 odd integers. The sum of 2 chosen integers will be odd, only if:
First is even and second is odd
First is odd and second is even
Mathematically the probability will be given by:
P(First is even) * P(Second is odd) + P(First is odd) + P(Second is even)

= (20/40) * (20/39) + (20/40) * (20/39)

= 20/39

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pankaj  (10 years ago)

20/40*20/39 + 20/40*20/39

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surbhi dubey  (10 years ago)

ans:-20c2/40c2+20c2/40c2

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