Average Practice Test 5

Score of the batsman in the 12th innings = 63 runs.
Average of 11th innings = x
Total score of 11th innings = 11x
Average after 12th innings $=\frac{11\mathit{x}+63}{12}=\left(\mathit{x}+2\right)$
$11\mathit{x}+63=12\mathit{x}+24$
$\mathit{x}=39$
Average after the 12th innings = 39