SOLUTION: Jason traveled 120 miles at an average rate of speed. If he could have increased his speed 25 mph, he could have covered the same distance in 2/5 of an hour less time. How fast did

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Question 103905: Jason traveled 120 miles at an average rate of speed. If he could have increased his speed 25 mph, he could have covered the same distance in 2/5 of an hour less time. How fast did he travel?
Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
120/X=120/(X+25)+.4
120/X=(120+.4X+25*.4)/(X+25)
120/X=(120+.4X+10)/(X+25)
120/X=(130+.4X)/(X+25) NOW CROSS MULTIPLY.
120(X+25)=130X+.4X^2
120X+3000=130X+.4X^2
.4X^2+130X-120X-3000=0
.4X^2+10X-3000=0
.4(X^2+25X-7500)=0
.4(X-75)(X+100)=0
X-75=-0
X=75 ANSWER FOR THE ORIGINAL SPEED.
75+25=100 FOR THE INCREASED SPEED.
SPEED
120/75=120/100+.4
1.6=1.2+.4
1.6=1.6