Answer:
Please see the answer below:
Explanation:
Part 1.
25x ≤ 600
Part 2.
15y ≤ 600
Part 3.
25x ≤ 15y
Part 4.
Stella sells pecan pies for $15 each and has enough supplies to make 40 pies;
which means, Stella earns each day;
15 x 40
= $600
Hence Stella has enough money to sign up for the trip.