SOLUTION: Fred took 7 h to drive from Cheyenne to Boothill, a total distance of 485. He drove most of the way at 80 km/h, but was slowed to 30 km/h for a time by a dust storm during the tri

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Question 1173681: Fred took 7 h to drive from Cheyenne to Boothill, a total distance of 485. He drove most of the
way at 80 km/h, but was slowed to 30 km/h for a time by a dust storm during the trip. How many
hours did he spend driving through the dust storm?
Found 2 solutions by Boreal, MathTherapy:
Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
x hours at 80 km/h
7-x hours at 30 km/h
80x+30(7-x)=485
80x+210-30x=485
50x=275 km
x=5.5 hours at 80 km/h or 440 km
1.5 hours at at 30 km/h or 45 km
1.5 hours
Answer by MathTherapy(10555)   (Show Source): You can put this solution on YOUR website!

Fred took 7 h to drive from Cheyenne to Boothill, a total distance of 485. He drove most of the way at 80 km/h, but was slowed to 30 km/h for a time by a dust storm during the trip. How many hours did he spend driving through the dust storm?
Let time spent driving through sand storm, be T

Then time NOT spent in a sand storm = 7 - T

We then get the following DISTANCE equation: 30T + 80(7 - T) = 485

30T + 560 - 80T = 485

30T - 80T = 485 - 560

- 50T = - 75

Time spent driving in sand storm, or  

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