9514 1404 393
Answer:
2.56
Explanation:
Multiply by (1+6e^(-.7t))/1000:
2000/1000 = 1 +6e^(-0.07t)
1 = 6e^(-0.07t) . . . . . . . . . subtract 1
e^(0.07t) = 6 . . . . . . . . . . multiply by e^(0.07t)
0.07t = ln(6) . . . . . . . . . take the natural log
t = ln(6)/0.07 . . . . . . . divide by the coefficient of t
t ≈ 2.55966 ≈ 2.56