A AND B CAN TOGETHER FINISH A WORK IN 30 DAYS. THEY WORKED TOGETHER FOR 20 DAYS AND THEN B LEFT. AFTER ANOTHER 20 DAYS, A FINISHED THE REMAINING WORK. IN HOW MANY DAYS A ALONE CAN FINISH THE JOB?  Choose the correct choice from the following
A) 40  B) 50  C) 54  D) 60  E) NONE OF THESE
(A+B)'S 20 DAYS WORK=(1/30*20)=2/3. REMAINING WORK=(1-2/3)=1/3.   NOW, 1/3 WORK IS DONE BY A IN 20 DAYS.   WHOLE WORK WILL BE DONE BY A IN   (20*3)= 
<gadget id="calculator">  (20*3)</gadget>
<output>60</output>
60 DAYS.   CORRECT OPTION:60
<result>D</result>
A AND B CAN TOGETHER FINISH A WORK IN 30 DAYS. THEY WORKED TOGETHER FOR 20 DAYS AND THEN B LEFT. AFTER ANOTHER 20 DAYS, A FINISHED THE REMAINING WORK. IN HOW MANY DAYS A ALONE CAN FINISH THE JOB?