Suppose you have 40 minutes to exercise at the gym and you want to use the stair machine and the stationary bike. how many minutes should you spend on each machine so that you burn 225 calories? stair machine: 5 cal/min stationary bike: 6 cal/min

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?