What is the probability of these two scenarios?

Question

A shipment of 13 microwave ovens contains 3 defective units. A restaurant buys three of these units. What is the probability of the restaurant buying at least two nondefective​ units?

The probability is _____ ?

Six sales representatives for a company are to be chosen at random to participate in a training program. The company has twelve sales​ representatives, two in each of six regions. What is the probability that the six sales representatives chosen to participate in the training program will be from only three of the six ​regions?

The probability is ______ ?

Answer 1

Help with the 1st question:

probability of getting 2 defective units: 3 C 2 * 10 C 1 / 13 C 3 (where n C r is number of combinations of n taken r at a time)

probability of getting 3 defective units: 3 C 3 * 10 C 0 / 13 C 3

add to get total probability of getting at least 2 defective units