Emma runs a farm stand that sells apples and blueberries. Each pound of apples sells
for $3 and each pound of blueberries sells for $1.25. Emma made $58.50 from selling
a total of 30 pounds of apples and blueberries. Write a system of equations that could
be used to determine the number of pounds of apples sold and the number of pounds
of blueberries sold. Define the variables that you use to write the system.