I think you mean P= 100/(1+ 30e^(-0.88t)) which is not what you wrote. You want to solve the equation .7= 100/(1+ 30e^(-0.88t)) That is the same as (1+ 30e^(-0.88t))/100= .70 which is the same as 1+ 30e^(-0.88t)= 70. Can you finish that?

So you want to solve 82(1- e^(-.39t))= 70. Divide both sides by 82 to getand

Assuming that air resistance is proportional to the velocity of a falling object, the velocity (in feet per second) of an object t seconds after it has been dropped is given by V=82(1-e^-.39t). When will the velocity be 70 feet per second? Show all of your work or explain how you came up with your solution.

Any help/guidance would be so much appreciated!! Thanks so much.

1- e^(-.39t)= 70/82= 35/41. Subtract 1 from both sides: -e^(-.39t)= 35/41- 1= (35- 41)/41= -6/41. Multiply both sides by -1 to get e^(-.39t)= 6/41. Can you finish that?