There are 4 black marbles and 6 red marbles in a box. Consider selecting one marble at a time from the box. What
is the probability that the first marble is black and the second marble is also black. Express the probability in fraction format. (Show all work. Just the answer, without supporting work, will receive no credit.)
a.) Assume the marble is selected with replacement.
b.) Assume the marble is selected without replacement.
justification for a and b: please show work