Answer:
74,074 years.
Explanation:
1 tb is equal to 1,000,000,000,000 bytes.
1.6 terabytes is equal to 1.6 x 1,000,000,000,000 = 1,600,000,000,000 bytes.
40 hour work per week and 50 weeks in a year means the person is typing 40 x 50 = 2,000 hours per year.
2,000 hours is equal to 2,000 x 60 = 120,000 minutes.
Characters typed per year, based on speed of 180 characters per minute, is equal to 180 x 120,000 = 21,600,000 characters.
21,600,000 characters per year = 21,600,000 bytes.
It would take approximately 1,600,000,000,000 / 21,600,000 = 74,074 years to fill up the hard drive.