<span>To begin you have to find the midpoint of the side with (2,4) and (-4,2) as vertexes.
[ 2 + -4 ] / 2, [ 2 + 4 ] / 2 ) = (-1, 3)
Then you have to find the point 2/3 of the distance from (0,-2) to (-1,3) =
(0 + (-1 - 0) (2/3) , -2 + ( 3 - -2)(2/3) )
( 0 - 2/3, -2 + (5)(2/3) )
(-2/3, -2 +10/3 )
The coordinates of the centriod of a triangle are (-2/3 , 4/3 )</span>
Number defective=4
number of non-defective=total-defective
=20-4
=16
the questions asked for 1 defective
so we choose only 1 defective from 4 defective items
4C1
and for 1 non-defective
we choose only 1 non-defective from 16 non-defective items
16C1
we choose 2 items from 20 items
so 20C2
answer:
probability= [(4C1) * (16C1)] /(20C2)
=32/95