Question 83738
A=Pe^(rt)
7000=700e^.42t

Solve for t:
7000/700=700/700e^.42t=
10=e^.42t
take the log of each side:
ln(10)=ln(e^.42t)  knowing the rules ln(e^rt)=rt  therefore:
ln(10)=.42t
ln(10)/.42=t
ln(10)=2.3025/.42=

5.48=t  YOUR ANSWER