flying against the wind, an airplane travels 5220 kilometers in 9 hours. flying with the wind, the same plane travels 6560 kilometers in 8 hours. what is the rate of the plane in still air and what is the rate of the wind?

Two farmers pay a total rent of $140 for a pasture. the first farmer placed $4 oxen in the pasture, and the second farmer placed $30 sheep in the pasture. the farmers split the rent based on the proportion of the pasture eaten by their own animals that month. how much should the first farmer pay, if 1 ox eats as much as 10 sheep in a month?