Solution:
Let’s take A1 to be the event of getting a total of \[6\]
\[{{A}_{1}}~=\text{ }\left\{ \left( 2,\text{ }4 \right),\text{ }\left( 4,\text{ }2 \right),\text{ }\left( 1,\text{ }5 \right),\text{ }\left( 5,\text{ }1 \right),\text{ }\left( 3,\text{ }3 \right) \right\}\]
And, B1 \[{{B}_{1}}\] be the event of getting a total of \[7\]
\[{{B}_{1}}~=\text{ }\left\{ \left( 2,\text{ }5 \right),\text{ }\left( 5,\text{ }2 \right),\text{ }\left( 1,\text{ }6 \right),\text{ }\left( 6,\text{ }1 \right),\text{ }\left( 3,\text{ }4 \right),\text{ }\left( 4,\text{ }3 \right) \right\}\]
Let \[P({{A}_{1}})\] is the probability if A wins in a throw = \[5/36\]
And \[P({{B}_{1}})\]is the probability, if B wins in a throw = \[1/6\]
Therefore, the required probability of wining A in his third throw