Answer:
It will double his salary every 8.04 years
Step-by-step explanation:
Using the future value of a lump sum formula we solve for time at which 45,000 principal becomes 90,000:
Principal: 45,000
time n
rate 0.09000
Amount: 90,000
to solve for n we use logartihmics properties:
![n= \frac{log90,000/45,000}{log(1+0.09)]()
n = 8.043231727 = 8.04 years