Mr.A has 13 cards of the same suit. He withdraws 4 cards from it and makes a number using the digits in the units place of each chosen card, i.e he will take 3 from king whose value is 13, 0 from 10, 9 from 9 and so on.. What is the probability that he can form a number that is divisible by 2?
My working(which is incorrect):
Since this question is dealing with combination. I could answer it as:
6C4/13C4 .. (6 possible ways to select numbers ending with an even digit with 4 chosen cards)
The correct answer according to the book is: (6 * 12 * 11 * 10)/(13 * 12* 11 * 10) = 6/13
The solution from the book went above my head. How do i solve this question?