Let A be the set of whole numbers bigger than 3 and smaller than 10 and B the set of positive whole numbers smaller than 8. Which of the following sets is equal to A U B?

1. during first 10 seconds 2. between 10 seconds and 35 seconds 3. during 35 seconds to 40 seconds

Adj has a total of 1075 dance and rock songs on her system. the dance selection is 4 times the size of the rock selection. write a system of equations to represent the situation.

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?