100 o
o7
9
In a sale everything is reduced by 15%.
A week later the prices are reduced by another 20%.
The shopkeeper says that all the prices have been reduced by 35%.
5
Show that the
shopkeeper is wrong. Reduce b
educe by ist
by !5​

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?