Harish can paint a wall in just 3 hours. However it takes 6 hours for Ganpat to complete the same job of painting the wall.
How long would it take for both of them to paint the wall , if both work together ?
Choose the correct choice from the following choices:  A) 3 Hours  B) 1 Hours  C) 3.20 Hours  D) 2 Hours  E) 1.35 Hours
D   Two hours.   Harish who could paint the wall in 3 hours could paint 2/3 of the wall in just two hours. Ganpat who paint the wall in 6 hours could paint 1/3 of the wall in two hours.   2/3 + 1/3= 
<gadget id="calculator">2/3 + 1/3</gadget>
<output>1</output>
1.
<result>D</result>
Harish can paint a wall in just 3 hours. However it takes 6 hours for Ganpat to complete the same job of painting the wall.
How long would it take for both of them to paint the wall , if both work together ?