Appropriate the intervals where each function is increasing and decreasing

The number of revolutions of two pulleys is inversely proportional to their diameters. if a 24-inch diameter pulley making 400 revolutions per minute is belted to an 8-inch diameter pulley, find the number of revolutions per minute of the smaller pulley.

Diana is painting statues she has 7/8 of a liter of paint each statue requires 1/20 of a liter of paint how many statues can she paint?

What are linear equations? could'ya explain too me, ? ! and how do you see what graph is a proportional relationship?