Let the initial salary be y.
now if we increase y by 25%, the value will become 32000.
It's equation is given as,
(we can also write 25% as 25/100) so
taking L.C.M. of y+(25/100)y we get,
now we take (125/100) to the other side of equation, it becomes its reciprocal as,
So his original salary was Rs.25600.