Answer :
2/40 simplifies to 1/20. Multiply both top and bottom by 5 and you get 5/100. So 5%.
Any time you are solving a problem with percentages, use the formula below
% = Is
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100 Of
Percent over 100 = "is" over "of"
In this case you are solving for percent and the "is" over "of" is $2 / $40
Then you cross multiply and divide.
100 x $2 = $200. 200 divided by 40 = 5. So the answer is 5