PLEASE HELP!! Determine whether y varies directly with x. If so, find the constant of variation k and write equation.
X 3, 12, 48, 192
Y 21, 84, 336, 1344
A. yes; k=7;y=7x
B. yes; k=4;y=4x
C. yes; k = 3 ; y = 3x
D. no

The radius of the base of a cylinder is 10 centimeters, and its height is 20 centimeters. a cone is used to fill the cylinder with water. the radius of the cone's base is 5 centimeters, and its height is 10 centimeters.

Abby is preparing fruit punch for her party. she starts with a bowl filled with liquid that has 1/2 fruit juice and 1/2 sprite, but she decides it's too fruity. so she pours out 1/4 of the liquid, and then fills the bowl up again with sprite. what fraction of the punch is now sprite?

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)