Question 103905
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