Solution :
Initial amount is : $1091 .
Rate, r = 0.12 .
Let, amount will be $1728 in t years.
So,
[tex]1728 = 1091( 1 + 0.12t )\\\\1 + 0.12t = \dfrac{1728}{1091}\\\\1 + 0.12t = 1.58\\\\0.12t = 0.58\\\\t = \dfrac{0.58}{0.12}\\\\t = 4.8\ years\\[/tex]
Hence, this is the required solution.
