Question 523196
Let x be the 		total sales									
Option I			500	+	0.04	x					
Option II			400	+	0.05	x					
Option I	=	Option II									
500+0.04x=400+0.05	x 	
500+0.04x=400+0.05x 	
500-400=0.05x-0.04x	
100	=	0.01	x 								
10000	=	x

CHECK									
$10000	should be total sales							
Option I500	+	0.04	*	10000=		900
Option II400	+	0.05	*	10000=		900


Option II is better offer . the income is more than that of option I when he sells for more than $10,000