Tilak's salary increases by 15% in the first year, decreases by 20% in the second year and increases by 25% in the third year. If Tilak's salary after these three years is Rs. 23,000, then find the salary of Tilak in the begianing of these 3 years.

Rs. 20,000

15% =  \(\frac{(3)}{20}\) , 20% = \(\frac{(1)}{5}\) & 25% = \(\frac{(1)}{4}\) 

Let Population two years ago = 100x
ATQ ,

 100x × \(\frac{(23)}{20}\) × \(\frac{(4)}{5}\) × \(\frac{(5)}{4}\) = 23000

100x = 20000