A and B can do a work in 60 days; B and C can do it in 120 days; A and C can do it in 80 days. In what time A alone can do the work?
Choose the correct choice from the following choices:
A) 100	B) 90	C) 80	D) 70	E) 60
(A+B)’s one day’s work = 1/60   (B+C)’s one day’s work = 1/120   (A+C)’s one day’s work = 1/80   Adding we get, 2(A+B+C)’ s one day’s work= 1/60 + 1/120 + 1/80   = 28/720   = 14/365   (A+B+C)’ s one day’s work = 14*1/365*2 = 14/720   So, A’s one day’s work = 14/720 - 1/120 = 1/90   A alone can do the work in 90 days.   ANSWER:90
<result>B</result>
A and B can do a work in 60 days; B and C can do it in 120 days; A and C can do it in 80 days. In what time A alone can do the work?