Answer:
After 28 years, it will be $131,200
Explanation:
It is given that the investment doubles in value every 7 years.
So, after 7 years, it will be 8200 × 2 = 16,400
After 14 years, it will be 16,400 × 2 = 32,800
After 21 years, it will be 32,800 × 2 = 65,600
After 28 years, it will be 65,600 × 2 = 131,200
Hence, the investment is $131,200 worth after 28 years.