Question 722402
Usual speed=	x   											
Distance =	273	miles										
speed increased by	7	miles/h										
{{{Time = distance / speed}}}												
												
It leaves 	 1/4	hour late	 reaches on time									
It takes 	 1/4	hour less										
												
Usual Time- time taken today =			 1/4									
												
273	/x-	273	/(x+	7	)=	 1/4						
												
Multiply by the LCD												
												
273	*	4	(x+	7	)-	273	*	4	x=	x(x+	4	)
1092	(x+	7	)-	1092	x=	X^2 +	4	x				
1092	x+	7644	-	1092	x=	X^2 +	4	x				
x^2+	4	x=	7644								
complete the squares												
												
(x+ 	2	)^2=	7644+	4								
take the square root												
												
x+  	2	=+/-	{{{sqrt(	7648	)}}}							
												
x+  	2	=+/-	87.45									
												
so x = 	85.45Usual speed=	x   											
Distance =	273	miles										
speed increased by	7	miles/h										
{{{Time = distance / speed}}}												
												
It leaves 	 1/4	hour late	 reaches on time									
It takes 	 1/4	hour less										
												
Usual Time- time taken today =			 1/4	4								
												
273	/x-	273	/(x+	7	)=	 1/4						
												
Multiply by the LCD												
												
273	*	4	(x+	7	)-	273	*	4	x=	x(x+	4	)
1092	(x+	7	)-	1092	x=	X^2 +	4	x				
1092	x+	7644	-	1092	x=	X^2 +	4	x				
x^2	4	x-	7644	=0								
complete the squares												
												
(x+ 	2	)^2=	7644	4								
take the square root												
												
x+  	2	=+/-	sqrt(	7648	)							
												
x+  	2	=+/-	87.45									
												
so x = 	85.45	mph	usual speed