Answer:
Step-by-step explanation:
25 = 64 / (1 + 14e^(-0.28x))
25(1 + 14e^(-0.28x)) = 64
25 + 350e^(-0.28x)) = 64
350e^(-0.28x)) = 39
e^(-0.28x)) = 39/350
-0.28x = ln(39/350)
x = (ln(39/350)) / -0.28
x = 7.8370...
x = 7.8 months
