To answer each question, use the function t(r) = dr
, where t is the time in hours, d
is the distance in miles, and r is the rate in miles per hour.
a. sydney drives 10 mi at a certain rate and then drives 20 mi at a rate 5 mi/h
faster than the initial rate. write expressions for the time along each part of
the trip. add these times to write an equation for the total time in terms of the
initial rate, ttotal(r).