Question: explain how i got this answer? 2 cards are selected at random from 10 cards numbered from 1 to 10.\nFind the probability P,\nthat the sum is odd, \n\ni)if 2 cards are drawn together\n\n The answer given is 25/45\n How is that possible,\nCan somebody explain me

Answer: Number of combinations of 2 cards  = 10C2 = 10!/(2!*8!) = 45\n\nFor odd combo we have\n1 with 2,4,6,8,10\n2 with 3,5,7,9\n3 with 4,6,8,10\n4 with 5,7,9\n5 with 6,8,10\n6 with 7,9\n7 with 8,10\n8 with 9\n9 with 10\n\nthe total number of pairs is 25\n\ntherefore, Probability is 25/45
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