How can i solve this : solve for q: (4q - 6n)/(3m) = f

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?

What percent of 18 is 24? and plz explain thx.

Which equation can be solved to find x the measure of jk in the apex