please assist in the attached documents and word problem
18. Suppose $3,500 is invested in an
account at an annual interest rate of 2.2% compounded continuously. How long (to the nearest tenth of a year) will it take the investment to double in size?
29 and 30 attached
29. The fuel efficiency F for a particular car is given by
F(x) = 0.02 x3 + 1.56 x + 9.8
where x is the speed of the car in miles per hour (mph) and A(x) is the corresponding fuel
efficiency in miles per gallon (mpg)-
(a) What is the fuel efficiency if the car’s speed is 70 mph?
(b) What speed will yield the maximum fuel efficiency? Show work.
=0. Show work.