The number of cars sold by Maruti increased by 25% in the year 1999 and then decreased by 10% next year. Find the total number of cars sold by Maruti in the year 2000, if in the year 1998 it sold 2lakh cars.

I've used successive percentage formula in this question i.e (a+b+ab/100) but still my answer isn't correct

from successive % formulae, we have:
25+(-10)+25(-10)/100
=25 -10-2.5
=12.5
therefore, for overall 12.5 % increase, there is a increase of 25000, hence the answer is 2.25 lakh.

2.25 lakhs

no need to use successive percentage formula for faster and easy solution follow a commoner approach.
As 1998 it was 2,00,000 in 1999 it was 25% more i.e 2,00,000 (1.25)=2,50,000 in 2000 it was decreased by 10% therefore 25,000 is 10% i.e. 2,50,000-25,000=2,25,000 your answer.

2.25 lakh

1998 it is 2,00,000 1999 2,50,000 2000 it will be 2,50,000-25000=225000