Answer to Question #311748 in Statistics and Probability for kimmy

Question

There are 7 defective light bulbs in a bin containing 80 light bulbs. In how many ways can you select at

least 6 defective light bulbs when you choose 8 light bulbs at random?

Answer 1

Let n = a + b + c, where n - number of ways of selecting at least 6, a - number of ways of selecting exactly 6, b - number of ways of selecting exactly 7, number of ways of selecting eactly 8

$n={7 \choose 6}*{73 \choose 1}+{7 \choose 7}+0=512$