Question 18707: Please help me out with this one. I went thru the other questions and didn't see this type of question. Thanks
Joe traveled 290 miles east of St. Louis. For most of the trip he averaged 70mph, but for one period of time he was slowed to 20mph due to a major accident. If the total time of travel was 7 hours, how many miles did he drive at the reduced speed?
Answer by venugopalramana(3286)   (Show Source):
You can put this solution on YOUR website! Joe traveled 290 miles east of St. Louis. For most of the trip he averaged 70mph, but for one period of time he was slowed to 20mph due to a major accident. If the total time of travel was 7 hours, how many miles did he drive at the reduced speed?
let the duration of travel at reduced speed of 20 mph be =x hrs
total duration of travel =7 hrs.
so duration of travel at normal speed of 70 mph =7-x hrs
distance = speed *time
distance travelled at reduced speed =20*x=20x
distance travelled at normal speed =70*(7-x)=70*7-70*x=490-70x
total distance travelled=20x+490-70x=290
490-290=70x-20x
200=50x
x=200/50=4 hrs.
so distance travelled at reduced speed =4*20 =80 miles
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