How do u solve this problem “15 = 2 − 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?

Write each of the following numerals in base 10. for base twelve, t and e represent the face values ten and eleven, respectively. 114 base 5 89t base 12

Do you mind if you guys me with this question i’m on number 8