If in a triangle $ABC$, $\frac{b+c}{11} = \frac{c+a}{12} = \frac{a+b}{13}$, then $\cos A$ is equal to (1) $5/7$ (2) $1/5$ (3) $35/19$ (4) $19/35$
If in a triangle $ABC$, $\frac{b+c}{11} = \frac{c+a}{12} = \frac{a+b}{13}$, then $\cos A$ is equal to\\
(1) $5/7$\\
(2) $1/5$\\
(3) $35/19$\\
(4) $19/35$