How to solve a problem including percent increase and decrease

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

What is the image of c for a 90° counterclockwise rotation about a? (3, 7) (-1, 3) (7, 3)

The krasnapolski is a top-of-the-line hotel in amsterdam, the netherlands. among their many services, they rent bicycles to guests. the bicycle checkout is open 24 hours per day 7 days per week and has 50 bicycles on hand. on average, 10 guests request a bicycle each day, arriving completely randomly at all times of the day during the spring and summer seasons. guests keep bicycles for four days on average, with a standard deviation of two days. how long does a guest on average have to wait for a bike? a. approximately 24 hours b. approximately 0.033 hours c. approximately 4 days d. approximately 47 minutes