SOLUTION: The Danville Express travels 280 mi. at a certain speed. If the speed had been increased by 5 mph, the trip could have been made in 1 hour less time. Find the actual speed. I ca

Question 458988: The Danville Express travels 280 mi. at a certain speed. If the speed had been increased by 5 mph, the trip could have been made in 1 hour less time. Find the actual speed. I cannot figure the formula to use to figure this problem. Can you please help me?
Michele
Answer by jorel1380(3719) (Show Source): You can put this solution on YOUR website!
280/x=280/(x+5)+1
280(x+5)=280x+(x)(x+5)
280x+1400=280x+x2+5x
x2+5x-1400=0
(x+40)(x-35)=0
x=35 or -40
Throwing out the negative answer, we get the speed of the Danville Express to be 35 mph
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280/35= 8 hours
280/40= 7 hours..
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