In $$1975$$ it was estimated that there were $$250000$$ lions in Africa.  Over $$40$$ years this figure has decreased by $$90\textbackslash\%$$.  What is the current estimate for the number of lions in Africa ? 
Overseas Competition->Knowledge Point->Word Problem Modules->Solving Problems Involving Fractions and Percentages->Finding the Base
A $$90\textbackslash\%$$ decrease means $$10\textbackslash\%$$ of $$250000 = 250000 \div 10 = 25000$$ of the lions remain. 