For this case we have the following equation: u (t) = 12 • 2 ^ t / 3 We equate the equation for u (t) = 50. We have then: 12 • 2 ^ t / 3 = 50 We clear the value of t: 2 ^ t / 3 = 50/12 log2 (2 ^ t / 3) = log2 (50/12) t / 3 = log2 (50/12) t = 3 * log2 (50/12) t = 6.2 years Answer: After 6.2 years 50 acres of wetland are infested by an invasive plant species