A AND B CAN DO A WORK IN 12 DAYS, B AND C IN 15 DAYS, C AND A IN 20 DAYS. IF A, B AND C WORK TOGETHER, THEY WILL COMPLETE THE WORK IN: Answers
A) 5 DAYS
B) 7 5/6 DAYS
C) 10 DAYS
D) 15 2/3 DAYS
E) NONE OF THESE
(A+B)'S 1 DAY'S WORK=1/12, (B+C)'S 1 DAY'S WORK = 1/15;   (A+C)'S 1 DAY'S WORK = 1/20   ADDING, WE GET : 2(A+B+C)'S 1 DAY'S WORK =(1/12+1/15+1/20)=12/60=1/5   (A+B+C)'S 1 DAY'S WORK = 1/10   SO, A, B AND C TOGETHER CAN COMPLETE THE WORK IN 10 DAYS.   10 DAYSORRE10 DAYST OPTION: 10 DAYS
<result>C</result>
A AND B CAN DO A WORK IN 12 DAYS, B AND C IN 15 DAYS, C AND A IN 20 DAYS. IF A, B AND C WORK TOGETHER, THEY WILL COMPLETE THE WORK IN: