A take twice as much time as B or thrice as much time to finish a piece of work. Working together, they can finish the work in 7 days. B can do the work alone in?
Pick one.
A) 19
B) 12
C) 11
D) 42
E) 114
Suppose A, B and C take x, x/2 and x/3 respectively to finish the work.   Then, (1/x + 2/x + 3/x) = 1/7   6/x = 1/7 =&gt; x = 42   So, B takes 21 hours to finish the work.   Answer: 42
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A take twice as much time as B or thrice as much time to finish a piece of work. Working together, they can finish the work in 7 days. B can do the work alone in?