<p>a bag contains 6 chipps, numbered 1 thru 6. if 2 chips are chosen at random without replacement and the vallues on those 2 chips are multiplied, what is the probability that this product will be greater than 20??</p>
<p>I figured out that the answer should be 2/15 but honestly i just don`t know if this is correct and how i did it :D Can someone explain pls ;)</p>
<p>EDIT: That's wrong, hold on, let me redo it...</p>
<p>6 P 2 = 6!/4! = 30 <--- number of permutations</p>
<p>Ways of getting >20: </p>
<p>4<em>6, 5</em>6, 6<em>4, 6</em>5</p>
<p>= 4/30 -> 2/15</p>
<p>we have numbers 1 2 3 4 5 6</p>
<p>1st step) find products of 1x2, 1x3, 1x4, 1x5, 1x6 (they are 2,3,4,5,6)
2) 2x3, 2x4, 2x5, 2x6 (6,8,10,12)
3) 3x4, 3x5, 3x6 (12,15,18)
4) 4x5, 4x6 (20,24)
5) 5x6 (30)</p>
<p>so, only two products are greater than 20 (24 and 30)
number of all possible products is 15
the answer is 2/15
as i see it)</p>
<p>ya i got 2/15 doing it right now</p>