Let cost price of the scooter be ₹ x.
If he sells the scooter at a loss of 25%, then
SP=x−25% of x=x−25100x= ₹ 75100x
and if he sells the scooter at a loss of 20 %, then
SP=x−20% of x=x−20100x=80100x
It is given that the difference in the two SP's is ₹ 4000.
∴ 80100x−75100x=4000⇒80x−75x100=4000⇒5x100=₹ 4000⇒x=4000×1005
= ₹ 80000
Hence, cost price of scooter is ₹ 80000.