When truckers are on long-haul drives, their driving logs must reflect their average speed. Average speed is the total distance driven divided by the total time spent driving. A trucker drove 3 hours on a freeway at 60 miles per hour and then drove 20 miles in the city. The trucker's average speed was 57.14 miles per hour.

a. Write an equation that models the situation.

b. How long was the trucker driving in the city to the nearest hundredth of an hour?

0.500 hour

Step-by-step explanation:

Givens

Distance

Total Distance on the highway = 3hr * 60 miles / hr = 180 miles Distance in the city = 20 miles Total Distance = 180 + 20 = 200 miles

Time

Time on the highway = 3 hours Time in the city = x

Formula

d / t = r

Solution

Average rate = 57.14 Total Distance / Total Time = average rate 200 / (3 + x) = 57.14 Multiply both sides by 3 + x 200 = 57.14 * (3 + x) Remove the brackets 200 = 57.14*3 + 57.14x Multiply the factors on the right 200 = 171.42 + 57.14x Subtract 171.42 from both sides. 200 - 171.42 = 171.42 - 171.42 + 57.14x So the subtraction 28.58 = 57.14x Divide by 57.14 28.57/57.14 = x x = 0.500 hour Answer

0.500 hour is the answer