Find the slope of the line that passed through 5,10 -5,10

Will used 20 colored tiles to make a design in art class. 5/20 of his tiles were red. what is an equivalent fraction for the red tiles?

If the scale factor between two circles is 2x/5y what is the ratio of their areas?

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?