Question 456643
let the original speed = x
increased speed = x+5
t=d/r
original time - time with increased speed = 1

150/x -150/(x+5)=1
x(x+5) is the LCD

150(x+5)-150x= x(x+5)

150x+750-150x=x^2+5x
x^2+5x-750=0

Find the roots of the equation by quadratic formula							
							
a=	1	,b=	5	,c=	-750		
							
b^2-4ac=	25	-	3000				
b^2-4ac=	3025			
{{{sqrt(	3025	)}}}=	55
{{{x=(-b+-sqrt(b^2-4ac))/(2a)}}}							
{{{x1=(-b+sqrt(b^2-4ac))/(2a)}}}							
x1=(	-5	+	55	)/	2		
x1=	25						
x2=(	-5	-55	) /	2			
x2= 	-30						
Ignore negative value		
speed = 25 mph