What operation is used. Is a multiplicarion between irrational numbers.
What is the amount collected
It must be multiplied 15.5 x 3.98
Replace 15.5 = 15+ 0.5
3.98 = 4-0.02
then 15x 4 + 0.5x4 - 15x(0.02) - 0.5x(0.02)
Then result 60 + 2 - 0.30 - 0.01
62 - 0.31 = 61.69