For two events $A$ and $B$,
$$\mathrm { P } ( B \mid A ) = \frac { 1 } { 4 } , \quad \mathrm { P } ( A \mid B ) = \frac { 1 } { 3 } , \quad \mathrm { P } ( A ) + \mathrm { P } ( B ) = \frac { 7 } { 10 }$$
what is the value of $\mathrm { P } ( A \cap B )$? [3 points]\\
(1) $\frac { 1 } { 7 }$\\
(2) $\frac { 1 } { 8 }$\\
(3) $\frac { 1 } { 9 }$\\
(4) $\frac { 1 } { 10 }$\\
(5) $\frac { 1 } { 11 }$