The difference between a positive proper fraction and its reciprocal is 9 / 20. Then the fraction is :	Choose the correct choice from the following choices:
A) 4/0
B) 4/1
C) 4/5
D) 4/2
E) 4/3
Explanation:   Let the required fraction be x. Then, (1 / x )- x = 9/20   1 - x^(2) / x = 9 / 20 =&gt; 20 - 20 * x^(2) = 9 * x.   20 * x^(2) + 9 *x - 20 = 0.   =&gt; (4 * x + 5) (5 * x - 4) = 0.   =&gt; x = 4 / 5.   Answer: 4/5) 4/5
<result>C</result>
The difference between a positive proper fraction and its reciprocal is 9 / 20. Then the fraction is :