Question

8. A bag contains 6 purple marbles and 7 white marbles. Two marbles are drawn at random. One marble is drawn and not replaced. Then a second marble is drawn. What is the probability that the first marble is white and the second one is purple? (2 points)

Answer 1

First of all, it'd be Probability(White marble) times Probability(Purple marble when 1 marble becomes less)

\(\Large \color{Black}{\Rightarrow {7 \over 13} \times {6 \over 12} }\)

Answer 2

@satellite73 not replaced

Answer 3

9. In how many different ways can you arrange 7 books on a shelf? (2 points)

Answer 4

This one is easy. 7 * 6 * 5 * 4 * 3 * 2 * 1, so 7!