in a box of 8 pens , a total of 2 are defective . if a customer buys 2 pens selected at random from the box , what is the probability that neither pen will be defective ?
"p ( neither pen is defective ) = 6 / 8 * 5 / 7 = 15 / 28 the answer is e ."
multiply(divide(subtract(8, 2), 8), divide(subtract(subtract(8, 2), const_1), subtract(8, const_1)))