Question

Solve,If two numbers are chosen from (1,2,….25) what is the probability that one of the numbers is twice greater than the other number?

Answer 1

hmmm... i'm not very good at these but i'll take a stab at it....

the total possible ways of taking 2 numbers out of 25 is 25 choose 2: 25 C 2
now there are 12 ways to choose those two numbers such that one number is twice the other...
so my answer(guess) would be: \(\large \frac{12}{\text 25 C 2} \) ????

Answer 2

The total possible is 25*24 right?

Answer 3

25 C 2 = (25 !)/[(2!)(23!)] = (25)*(24)/[2] = 25*12