Solution:
From given,
Principal = $ 50, 000
Total amount = $ 177, 500
Rate of interest = 15 %
Number of years = ?
Interest amount = Total amount - principal
Interest amount = 177, 500 - 50, 000
Interest amount = 127500
Use the formula,
[tex]Interest = \frac{p \times n \times r}{100}\\\\127500 = \frac{ 50000 \times n \times 15}{100}\\\\127500 = 500 \times 15 \times n\\\\75n = 1275\\\\n = 17[/tex]
Thus he invested for 17 years
