A wheel barrow weighs $31\text{kg}$~when full of soil. Jill removes~$\dfrac{1}{5}$~of the soil from the wheel barrow and it now weighs $27\text{kg}$. What is the weight of the wheel barrow when it is empty? 
Overseas Competition->Knowledge Point->Word Problem Modules->Solving Problems Involving Fractions and Percentages->Finding the Base