Question 971873
Carpenter's rate of work = 1/2 units per hour
Assistant's rate of work = 1/3 units per hour
Their combined rate of work = {{{(1/2) + (1/3)}}} units per hour
={{{5/6}}} units per hour 
So, time required to do the job together
= {{{1/(5/6)}}} hours
= {{{6/5}}} hours