The total number of Silver medals won by countries C, D and F is approximately what per cent of the total medals won by countries A, B and C together?

Total number of Bronze and Silver medals won by Country C = 42 - 16 = 26 and the ratio of silver medals to bronze medals = 6:7.
So, the number of silver medals = $$\frac{6}{13}\times\ 26\ =\ 12$$.
Similarly, Silver medals won by D and F are 8 and 15 respectively.
Total Silver medals won by C, D and F = 12 + 8 + 15 = 35.

Total medals won by A, B and C together = 40 + 38 + 42 = 120.
Required percentage = $$\frac{35}{120}\times\ 100=29.16\%\approx\ 29.2\%$$.