Question

A farmer plants wheat and rye.

The farmer needs to plant at least 3 acres of rye, but no more than 15 acres of rye.
The farmer needs to plant at least 1 acre of wheat, but no more than 7 acres of wheat.
The farmer has up to 20 acres available for planting wheat and rye.
Each acre of wheat makes a profit of $500.
Each acre of rye makes a profit of $300.
Identify the variables in this situation.