The efficiency of P, Q, R, S are in the ratio of 6 : 5 : 4 : 3. If P and R can do a work together in 6 days. Then How much days Q and S will take to complete the same work?
1
\(7\frac{1}{2}\) days
2
\(8\frac{1}{3}\)days
3
10 days
4
18 days
5
None of these