Is 11/20 greater or less than 1/2

The head librarian at the library of congress has asked her assistant for an interval estimate of the mean number of books checked out each day. the assistant provides the following interval estimate: from 740 to 920 books per day. what is an efficient, unbiased point estimate of the number of books checked out each day at the library of congress?

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Consider that lines b and c are parallel. what is the value of x? what is the measure of the smaller angle?