20 total students
4/20 students have hazel eyes
which means 16/20 students do not have hazel eyes
16 divided by 20 =.8
there is an 80% chance that ONE is not hazel
and there is an 80% that the second isn't hazel
to find the probability that both will not be hazel
multiply 80% by 80% (.8 * .8)
.8 *.8 = .64
There is a 64% chance both of the selected students wont have hazel eyes