The distribution of grade point averages (GPAs)

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The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

Which of the following is the inverse of y = 3∧x y = 1/3∧x y = ㏒3x y = (1/3) ∧x y = ㏒ 1/3∧x