Find the sum of geometric series described as: a1=10, n=20, r=1.5

Question

how do i work it?

Answer 1

a1 = 10, n = 20, r = 1.5

Sum of geometric series = a(r^n -1)/r-1

S n = 10[(1.5)^20-1]/1.5-1

= 10(3325.25-1)/0.5

= 10(3324.25)/0.5

= 10*6648.51

= 66485.13