Speed P6 2010 SA2 Maha Bodhi Q15

10/SF + 10/SS = 13 1/3

                       = 40/3

1/SF + 1/SS = 1/10 x 40/3

                    = 4/3

24/SF + 6/SS = 14

18 SF = 14 - 6 x 4/3

 SF =  1/18 x 18/3

      = 3

30/3 = 10 s

It was 10 s.