Luther and nicole were on a hiking trip. they began at an elevation of 139m above the sea level and descended to an elevation of 21 m below sea level in 8h.
a)write a divison expression that can be used to find their average change in elevation per hour
b)use an integer to represent their average change in elevation per hour

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?