SOLUTION: a motorist drove his car 200mi. If his speed has been 5 mph faster he could have saved 2hrs travel time, what was his speed?

Question 765294: a motorist drove his car 200mi. If his speed has been 5 mph faster he could have saved 2hrs travel time, what was his speed?
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
a motorist drove his car 200mi. If his speed has been 5 mph faster he could have saved 2hrs travel time, what was his speed?
***
let x=
x+5="if" speed
travel time=distance/speed

LCD:x(x+5)
200(x+5)-200x=2x^2+10x
200x+1000-200x=2x^2+10x
2x^2+10x-1000=0
x^2+5x-500=0
(x-20)(x+25)=0
x=-25 (reject, x>0)
or
x=20
original speed= 20 mph

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