Answer: The best estimate for how much money she will make when it sells, rounding the original values, is between $36 and $57.
Solution:
The mural is 2.6 m, this value is between 2 m and 3 m.
She charges $18.50 per meter, this value is between $18 and $19 per meter.
The estimate for a minimum value is the multiplication of the smallest values:
($18/m)(2 m)=$36
The estimate for a maximum value is the multiplication of the largest values:
($19/m)(3 m)=$57
The best estimate for how much money she will make when it sells is between $36 and $57.