It seems that you came up with the same answer: (1*25 + 1*25) / 50*49.The answer is 2*25 / 50*49
I am not sure I understood what you said. Multiply by (2*25)?Is this approach correct. The answer indicates that I have to multipy (2*25).
There are 50 cards numbered from 1 to 50.
Two different cards are chosen at random. What is the probability that one number is twice the other number?
The answer is 2*25 / 50*49
I tried to split it in two cases. Case1, I get the lower card first (2,4) and case2, I get the higher number first (4,2).
case1:
__ __ First place has 25 choices (1-25), second place then has only 1 choice
case2:
__ __ First place has 25 choices (26-50), second place then has only 1 choice
Then I would add it up: 1*25 + 1*25
The total amount of ways to combine two cards would be 50*49 (First place has 50 choices and second place has 50-1 card which was already used)
The probability is then 1*25 + 1*25 / 50*49
Is this approach correct. The answer indicates that I have to multipy (2*25).
Thanks.