Math
posted by Jose on .
A and B caan finish typing a manuscript in 8/3 days; B and C together, in 40/9 days; A and C together in 20/7 days. How long will each, working alone type the manuscript?

work done = (actual time worked) / (req'd time to finish a task)
'completed' work = 1
so let
A = time req'd for A
B = time req'd for B
C = time req'd for C
there will be 3 equations:
(8/3A) + (8/3B) = 1
(40/9B) + (40/9C) = 1
(20/7A) + (20/7C) = 1
use elimination method to solve the problem. 
So if i eliminate C first would the resulting two equations be:
(8/3A) + (8/3B) = 1
(1/A) + (1/B) = (8/20)
???????