Could you please show me how to calculate this:

The quality control process at a manufacturing plant requires that each lot of finished units be sampled for defective items. Twenty units from each lot are inspected. If five or more defective units are found, the lot is rejected. If a lot is known to contain 10% defective items, what is the probability that the lot will be rejected and accepted?

This is a binomial probability.

Probability rejected:

\sum_{k=5}^{20}C(20,k)(\frac{1}{10})^{k}(\frac{9}{ 10})^{20-k}

A polling firm is taking a survey regarding a proposed new law. Of the voters
polled, 30% are in favor of the law. If 10 people are surveyed, what is the
probability that 4 will indicate that they are opposed to the passage of the new