Question

number of boys increases at5% per year. find number of boys in 2003 if there are 12000 boys in 2004

Answer 1

11428..men it's not in normal form it is in decimals

Answer 2

Number of boys increases at 5% per year. It means that every year number of boys increases by 5 per 100 boys.
In 2004 there are 12000 boys containing 100% +5 % of the total boys in 2003.
So, 105 % = 12000
100% = (12000×100)/105 = 11428 (ignore the decimal as the number of boys can't be expressed in decimal).

I hope this answers your question sufficiently. Happy learning.