The chances of a defective screw in three boxes A, B, C are \(\frac{1}{5},{\rm{\;}}\frac{1}{6}\) and \(\frac{1}{7}\) respectively. A box is selected at random and a screw drawn from it at random is found to be defective. Find the probability that it came from box A.
1
\(\frac{{40}}{{107}}\)
2
\(\frac{{41}}{{107}}\)
3
\(\frac{{42}}{{107}}\)
4
\(\frac{{43}}{{107}}\)
5
Not Attempted