Mary wants to fill in a cylinder vase. at the flower store they told her that the vase should be filled 3/4 for the flowers to last the longest. her cylinder vase has a radius of 4 inches and a height of 10 inches. how much water should mary pour into the vase?

First we need to find what is the volume of the vase.

Volume of a cylinder we calculated by:
V = r^2*pi*h     where r is radius and h is height.
V = 4^2 * 3.1415* 10
V = 502,64 inch^3

Now, since vase should be filled 3/4 of its volume, the volume of water that needs to be poured in is:
Vw = 3/4*V = 378 inch^3

C. i believe it is (5×(-20))+(100×(0.7))