The difference between a positive proper fraction and its reciprocal is 9/20. The fraction is:

Answer: Option C

Explanation:

Let the required fraction be x. Then	1	- x =	9
	x		20

	1 - x²	=	9
	x		20

20 - 20x² = 9x

20x² + 9x - 20 = 0

20x² + 25x - 16x - 20 = 0

5x(4x + 5) - 4(4x + 5) = 0

(4x + 5)(5x - 4) = 0

x =	4
	5