Question

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) . b. Determine the reasonable domain and range and describe any discontinuities of ttotal (r) . Graph ttotal (r) on your graphing calculator. c. At what rate, to the nearest mi/h, must Sydney drive if the entire 30 mi must be covered in about 45 min? Find the answer using the graph and using algebraic methods. d. How long will Sydney

Answer 1

Do you know the formula on how distance, rate, and time are related?

Answer 2

hello?

Answer 3

To answer each question, use the function t(r) = d , where t is the time in hours, d
r
is the distance in miles, and r is the rate in miles per hour.
is this what you need?

Answer 4

I"m really confused :(

Answer 5

yes.... the formula on how these quantities are related is

Distance = rate x time or simply: \(\large d = r \cdot t \)

Answer 6

so for the first part, "Write expressions for the time along each part of the trip", she travelled at two rates, let's call them t1 and t2, where:

t1 = rate travelled for the first part, and
t2 = rate travelled for the second part (notice Sydney travelled 5 mph more than t1)

so your formula will now be \(\large d=r \cdot (t_1+t_2) \), agree?

Answer 7

Agree