Elijah made 100 brownies this week. he baked 4 more than three times the total he made last week. how many brownies did he bake last week?

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?

Jonathan can type 20 documents in 40 minutes ,and susan can type it in 30 minutes and jack can type it in 24 minutes working together ,how much time will it is take them type the same document

Which one is the correct answer, and why?