Pipe Q can fill a tank in 10 hours and pipe R can empty the tank in 14 hours. If both the pipes are opened and after 3 hours R is closed then in how much time Q will take to fill the remaining tank?
1
\(4 \dfrac{1}{4}\) hours
2
\(7 \dfrac{3}{4}\) hours
3
\(6 \dfrac{1}{4}\) hours
4
\(9 \dfrac{1}{7}\) hours
5
\(5 \dfrac{3}{4}\) hours