Discussion :: Time and Work

A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in :
Answer : Option C
Explanation :
(A + B)'s 1 day's work =[\( \frac { 1 } { 15} \)+\( \frac { 1 } { 10} \)]=\(\frac { 1 } {6 } \)
Work done by A and B in 2 days =[\(\frac { 1 } {6 } *2]\)=\(\frac { 1 } {3 } \)
Remaining work =[1\(\frac { 1 } {3 } \)]=\(\frac { 2 } {3 } \)
Now, \(\frac { 1 } {15 } \)work is done by A in 1 day.
\(\frac { 2 } {3 } \)work will be done by a in[15\( *\frac { 2 } { 3 } \)]= 10 days.
Hence, the total time taken = (10 + 2) = 12 days.
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