Which is the best estimate for the length of a real chalkboard?

Subscriptions to a popular fashion magazine have gone down by a consistent percentage each year and can be modeled by the function y = 42,000(0.96)t. what does the value 42,000 represent in the function?

Awindow washer cleans 42 windows in 2 hours. at this rate, how many windows did he clean in 180 minutes.

Point r divides in the ratio 1 : 5. if the coordinates of e and f are (4, 8) and (11, 4), respectively, what are the coordinates of r to two decimal places?