Answer
(a) At an inch, the vertical distance of the function is $y=2^1=2in$.
At $2 ft=24in$, the height of the graph would be $y=2^{24}=16777216in=16777216/63360=264.8\approx265mi.$
(b) For $y=log_2x$, let $y=2ft=24in$, we have $log_2x=24,x=2^24=16777216in\approx265mi.$
Work Step by Step
see above.