in a box of 9 pens , a total of 3 are defective . if a customer buys 2 pens selected at random from the box , what is the probability that neither pen will be defective ?
n0 = 9.0
n1 = 3.0
n2 = 2.0
t0 = n0 - n1
t1 = n0 - 1.0
t2 = t0 / n0
t3 = t0 - 1.0
t4 = t3 / t1
answer = t2 * t4
print(answer)