Monday=92
Tuesday=88
Wednesday=87
Thursday=91
Friday=88
There are 88 fish remaining
This can be solved using the system of equations:
5500 = 1000c + 1500s
5 = c + s
As the first equation can have different combinations, it is the second equation that defines just how much acres or corn or strawberries(or mathematically, it defines the values of c or s in the first equation) there are. Therefore, the equation " 5 = c + s" is the constraint.