Answer:
The number of years is 15 years
Explanation:
From the question we are told that
The present value is

The year payment required to reach future goal is

The future goal is

The interest per year is

The negative sign shows that the fund are not gain made but they are being deducted
Using the excel formula NPER (r , PMT , PV , FV , 0 )
Here the 0 stands for type
The implantation on excel is shown on the first uploaded image