Question

The proportion of the defective items is 0.20 if 10 are selected what is the probability that none is defective

Answer 1

Probability that the selected item is not defective equals $1-0.2=0.8.$ Then probability that 10 selected items are not defective equals $(0.8)^{10}\approx 0.107$ (events "the first is not defective",$\ldots$, "the tenth is not defective" are independent collectively).