Which ratio is equivalent to 4:5? A. 10/15
B. 4/10
C. 16/20
D. 15/8

Help me please

1. writing an equation for an exponential function by 2. a piece of paper that is 0.6 millimeter thick is folded. write an equation for the thickness t of the paper in millimeters as a function of the number n of folds. the equation is t(n)= 3. enter an equation for the function that includes the points. (-2, 2/5) and (-1,2)