Which situation does the expression 4(-500) model? A) An airplane ascends at an average rate of 4 feet per minute for 500 minutes.
B) An airplane descends at an average rate of 4 feet per minute for 500 minutes.
C) An airplane ascends at an average rate of 500 feet per minute for 4 minutes.
D) An airplane descends at an average rate of 500 feet per minute for 4 minutes.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Aretha wanted to gather data about the cost of local bowling leagues in her area. she plotted the data and determined that the average bowling league costs consist of a one-time registration fee and a monthly fee modeled by the equation y = 15x + 20. identify and interpret the y-intercept in this model. the y-intercept is 20. this is the cost per month. the y-intercept is 20. this is the cost of registration. the y-intercept is 15. this is the cost of registration. the y-intercept is 15. this is the cost per month.

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?