A batsman has a certain average of runs for 24 innings. He scores 124 runs in his 25th innings thus his average increased by 3. Find the average after 25 innings.

let average of 24 innings = x

He score 124 runs in 25^th $inning$ 

then,Average increased by 3

$average$ $after 25th innings=x+3$

$score in$25 innings $=25(x+3)$

$score in$ 24 innings $=24x$

$\begin{array}{l}25(x+3)=24x+124\\ 25x+75=24x+124\\ x=124-75\\ x=49\end{array}$

=49+3=52