What is the simplest form of $$2$$ yards $$:30$$ feet? (Note that $1$ yard is equal to $3$ feet)． 
Overseas Competition->Knowledge Point->Calculation Modules->Ratios and Proportions->Ratio
We need to make the units same first. $$2$$ yards equal to $$6$$ feet. Now we could remove the same unit, feet. We get $$6:30$$ and simplify it to $$1:5$$. 