A certain fraction is equivalent to 3/5. If the numerator of the fraction is increased by 4 and the denominator is doubled, the new fraction is equivalent to 1/3. What is the sum of the numerator and denominator of the original fraction?  Choose one
A) 49  B) 35  C) 28  D) 56  E) 21
x/y = 3/5 -&gt; 1   (x+4)/2y = 1/3 -&gt; 2   56ivide 1 by 2 :   =&gt; 2x/(x+4) = 9/5   =&gt; 10x = 9x + 36   =&gt; x = 36   =&gt; y = 5/3 * 12= 
<gadget id="calculator">5/3 * 12</gadget>
<output>20</output>
20   so x + y= 56   The answer is 56.
<result>D</result>
A certain fraction is equivalent to 3/5. If the numerator of the fraction is increased by 4 and the denominator is doubled, the new fraction is equivalent to 1/3. What is the sum of the numerator and denominator of the original fraction?