Question: Please answer the following questions on probability.

(a) Consider the task of choosing 2 marines from a platoon of 6 to send on a dangerous mission. How many different selections of 2 can be made?

(b) Suppose you are considering planting 5 different types of trees, from a selection of 10 different types of trees (e.g. oak, maple, birch, walnut, flowering dogwood, etc.), side-by-side in your yard to act as a “natural fence” between you and your neighbor’s yard. How many different arrangements of trees are there for your “natural fence’?