A, B, and C are three pipes that fill a tank. A and B together can fill a tank in 6h. B and C can fill a tank in 10h and A and C can fill a tank in 12h. In how much time A, B, and C can fill a tank together?
1
9h
2
\(5\frac{3}{7}\;{\rm{hr}}\)
3
\(5\frac{2}{7}\;{\rm{hr}}\)
4
\(5\frac{5}{7}\;{\rm{hr}}\)
5
None of these