Question

by selling a pen for rupees 60 Shalini gains 25% find the CP of the pen

Answer 1

Let the CP of the pen be x
Gain of 25% means SP will be
x+(25/100×x)=x+x/4=5x/4
But 5x/4=60
or 5x=60×4
or x=60×4/5
or x=48
Therefore the CP of the pen was Rs 48.

I hope the answer is all correct.
Sorry if I am wrong.