RRB NTPC Mains or Stage 2 Model Paper 7 with solutions

(d) To calculate faster, instead of finding all the students of (a)rts and Science stream first and then subtracting, let’s assume that in each college Science students are more and keep substracting the number of (a)rtsstudents from the number of Science students college wise.
Difference =$\left(40\%\mathit{o}\mathit{f}17500\mathit{–}25\%\mathit{o}\mathit{f}17500\right)+\left(40\%\mathit{o}\mathit{f}25000\mathit{–}15\%\mathit{o}\mathit{f}25000\right)+\left(55\%\mathit{o}\mathit{f}35300\mathit{–}15\%\mathit{o}\mathit{f}35300\right)+\left(24\%\mathit{o}\mathit{f}23000\mathit{–}28\%\mathit{o}\mathit{f}23000\right)+\left(41\%\mathit{o}\mathit{f}32400\mathit{–}29\%\mathit{o}\mathit{f}32400\right)$
$=\left(15\times 175\right)+\left(25\times 250\right)+\left(40\times 353\right)+\left(\mathit{–}4\times 230\right)+\left(12\times 324\right)$
$=2625+6250+14120\mathit{–}920+3888$
$=25963$