A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With help of C, they did the job in 4 days only. Then, C alone can do the job in:	Choose one.
A) 7 4/5 B) 9 3/5 C) 4 1/6 D) 7 7/12 E) 8 6/7
A + B + C's 1 day's work = 1/4   A's 1 day's work = 1/16   B's 1 day's work = 1/12   Therefore C's 1 day's work = 1/4	- ( A's 1 day's work + B's 1 day's work )   =&gt; C's 1 day's work = 1/4 - ( 1/16 + 1/12 )   =&gt; C's 1 day's work = (12-3-4)/48 = 5/48   So, C alone can do the work in 48/5 = 9 3/5 days.   So correct answer is 9 3/5
<result>B</result>
A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With help of C, they did the job in 4 days only. Then, C alone can do the job in: