Solution: Set $ 3^t = 9^t-1 $. Since $ 9 = 3^2 $, rewrite the equation as $ 3^t = (3^2)^t-1 $. Simplify the right-hand side: $ 3^t = 3^2(t-1) $. Equate the exponents: $ t = 2(t - 1) $. Solve: $ t = 2t - 2 $, so $ t = 2 $. Verify by substituting back: $ 3^2 = 9^1 $ → $ 9 = 9 $. Thus, the time is $ \boxed2 $. - Groen Casting