Question

I will take a picture of the question there are like four parts to this question

Answer 1

Use A= Ao•e^kt

then

2Ao = Ao•e^kt

cancel Ao, then

2 = e^kt

then

Ln 2 = kt

now find t

t = Ln 2/k

Answer is , all steps gives as result

t = Ln 2/k