A number increased by a% and decreased by 80% is 400. What is the number?

updated response , given that you confirmed the question....

if the percent is the variable a% then ....

I think that there is missing information here ....

you can make any number work here the result of the number being increased by the percent has to be 2000...

so if if the number is 1000 then the percent would be 100%

if you make the number  1500 then the percent would be 33 1/3 %

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