First we must find the price of the camera after the man sold it, with the 10% loss.
To do this we find 10% of 414, which is 41.4 . Meaning the camera was originally bought from the dealer for $455.40, as we have to add the 10% back onto the price.
Now we find 15% of 455 and subtract it, with 15% being 68.25, the original cost was $386.75. My guy was seriously ripped off :(.
After 28 mins you've gone 4 miles, assuming this rate is constant and you dont slow down or speed up, in order to get to 20 miles you will have run 5x as much (20/4 = 5), thus 5x the amount of time (28x5).
