Giving out free points

Jonah runs 3/5 miles on sunday and 7/10 mile on monday. he uses the model to find that he can ran a total of 1 mile . what mistake does jonah make

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?

Linda loans her friend $250 with a 5% monthly intrest rate. how much was the whole loan?