Question

A person takes a trip, driving with a constant peed of 89.5 km/h, except for a 22.0-min rest stop. If the peron's average speed is 77.8 km/h, (a) how much time is spent on the trip and (b) how far does the person travel?

Answer 1

Answer:

a) The person traveled 2.83 hours.

b) The person travels 220.17 kilometers.

Step-by-step explanation:

We have that the speed is the distance divided by the time. Mathematically, that is

$s = \frac{d}{t}$

(a) how much time is spent on the trip and

The peron's average speed is 77.8 km/h, which means that $s = 77.8$

The person distance traveled is:

22 min is 22/60 = 0.37h.

So for  the time t1, the person traveled at a speed of 89.5 km/h. Which has a distance of 89.5*t1.

For 0.37h, the person was at a stop, so she did not travel. This means that the total distance is

$d = 89.5t1 + 0 = 89.5t1$

The total time is the time traveling t and the stoppage time 0.37. So

$t = t1 + 0.37$

We want to find t1, which is the time that the person was driving.

So

$s = \frac{d}{t}$

$77.8 = \frac{89.5t1}{t1 + 0.37}$

$77.8t1 + 77.8*0.37 = 89.5t1$

$11.7t1 = 28.786$

$t1 = \frac{28.786}{11.7}$

$t1 = 2.46$

The total time is

$t = t1 + 0.37 = 2.46 + 0.37 = 2.83$

The person traveled for 2.83 hours.

(b) how far does the person travel?

The person traveled 2.46 hours at an average speed of 77.8 km/h. So

$s = \frac{d}{t}$

$77.8 = \frac{d}{2.83}$

$d = 77.8*2.83 = 220.17$

The person travels 220.17 kilometers.