I'm having trouble with the following:
An international organization must decide how to spend the $2,000 they
have been allocated for famine relief in a remote area. They expect to
use the money to buy rice at $5 per sack and beans at $10 per sack.
The number P, of people who would be fed if they buy x sacks of rice
and y sacks of beans is given by
What is the maximum number of people who can be fed and how much
of each food should the organization purchase?