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Which of the following is the explicit rule for a geometric sequence defined a recursive formula of a -5a for which the first term is 23?

Order the measurements from the least to the greatest. 2,720 ml , 24.91 l , 0.0268 kl

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?