Help with these 2 pls!

Cam bought some used books for $4.95. he paid $0.50 each for some books and $0.35 each for the others. he bought fewer than 8 books at each price. how many books did cam buy?

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Suppose a pendulum is l meters long. the time,t,in seconds that it tales to swing back and forth once is given by t=2.01