Sum of simple interest annuity with increase in rate every year

[marzban]

Hi all,

Analyzing an Insurance policy which pays an annuity which increases by 5% every year (simple). So if the annuity is Rs. 100 in the first year, it will be Rs. 105, 110, 115, 120 etc, in succeeding years, going up to 195 in the 20th (Final) year.

Given:
Starting annuity amount in cell A1
number of benefit years in A2
increase rate (simple, 5%) in A3

What would be the formula to calculate the Total annuity amount received over the number of benefit years?

Thanks in advance!
Marzban

 

[herofox]

please Upload the file with explaination ?!!

 

[Chihiro]

May be...
=(A1*A2)+SUM(A1*A3*ROW(INDIRECT("1:"&A2-1)))

Confirmed as array (CTRL + SHIFT + ENTER)