Let a be original height
r the ratio of bounce
so we get
a
after first bounce ar
after second bounce = ar^2
a) after n bounce = ar^n
b) distance travelled first bounce = a+ar
distance travelled second bounce = a+ ar+ ar+ ar^2
( ar going up and down so twice)
distance travelled third bounce = a+ar+ar+ar^2+ar^2+ar^3
distance travelled fourth bounce = a+ar+ar+ar^2+ar^2+ar^3+ar^3+ar^4
c) a+ 2(ar+ar^2+ar^3+...ar^(n-1) ) + ar^n
= 2(a+ ar+ar^2+ar^3+...ar^(n-1) + ar^n ) - a - ar^n
= 2a(1 -r^(n+1) )/(1-r) - a - ar^n
substitute a = 10 and r = 3/4 to get answers
