There are 10 students in a class: 6 boys and 4 girls. if the teacher picks a group of 3 at random, what is the probability that everyone in the group is a girl?

Probability that nbr1 is a boy is p1 = 6/10.

Probability that nbr2 is a boy, given 5 boys left is 5/9

Probability that nbr3 is a boy given 4 boys left is 4/8

Probability that nbr 4 is a boy given 3 boys left is 3/7

Step-by-step explanation:

so its 4%

yo answer should be 6 if im not mistaken

step-by-step explanation:

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12