20)
if we take 392 to be the 100%, what is 98 off of it in percentage?

22)
let's say is "x", so if "x" is the 100%, and we know that 145 is the 33%, what the dickens is "x"?

24)
again, if we take "x" to be the 100%, and we know that 17 is 40%, what is "x"?
