Question 856429
Boat speed	=	48	mph										
current speed	=	x	mph										
													
speed against	current	48	-	x									
speed with	current	48	+	x									
													
Distance against	current	132	miles										
Distance with	current	156	miles										
													
t=d/r	time against = time with		current	-									
132	/	(	48	-	x	)=	156	/	(	48	+	x	)
132	(	48	+	x 	)=	156	(	48	-x	)			
6336	+	132	x	=	7488	-	-156	x					
156	x	132	x		7488	+	-6336						
288	x	=	1152										
/	288												
x	=	4	mph	current	speed