Question 719993
biker speed	=	12	mph										
windspeed	=	x	mph										
													
speed against	wind	12	-	x									
speed with	wind	12	+	x									
													
Distance against	wind	38	miles										
Distance with	wind	58	miles										
													
t=d/r	time against = time with		wind	-									
38	/	(	12	-	x	)=	58	/	(	12	+	x	)
38	(	12	+	x 	)=	58	(	12	-x	)			
456	+	38	x	=	696	-	-58	x					
58	x	38	x		696	+	-456						
96	x	=	240										
/	96												
x	=	2.5	mph	wind	speed