Will is selling apples at the farmer\textquotesingle s market. After selling $\dfrac{2}{5}$ of them, he has $150$ left. How many apples did Will have to start with? 
Overseas Competition->Knowledge Point->Word Problem Modules->Solving Problems Involving Fractions and Percentages->Finding the Base
He has $\dfrac{3}{5}$~remaining after selling $\dfrac{2}{5}$. We can write the equation as:~$150\div\dfrac{3}{5}=250$. 