Find the unit rate for 90% books to 10% magazines. (Consider the unit rate to be the number of books per magazine.).

Evaluate the following expression 1/3^2

∆red ≅ ∆ by rule will give brainiest if possible

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?