This is one of the problems we worked on in math class:
Joe wants 40 pies. He is wondering what 40 is 20% of because that would be even more pies. 40 is 20% of what.
40=20%of what number?
For thus problem I thought 20% is the same as 1/5 of 100. Since 40 is double of 20 then it must be 200 because your also doubling the 100.