If 50% of (x – y) = 30% of (x + y), then what percent

According to question ,
50% of (x – y) = 30% of (x + y)

⇒	1	(x - y) =	3	(x + y)
	2		10

⇒	x	-	3x	=	3	y +	y
	2		10		10		2

⇒	5x - 3x	=	3y + 5y
	10		10

⇒	x	=	4y
	5		5

∴ x = 4y

⇒ y =	x	⇒ y =	x	× 100 % = 25x
	4		4

Obviously, y is 25% of x