Answer: 20 pounds.
Step-by-step explanation:
We know the weight of each flower arrangement (each one weighs 6 2/3 pounds) and the total number of flower arrangaments Isabelle ordered (3 flower arrangements).
To make the calculus easier, we can rewrite the mixed number 6 2/3 as a decimal number:
Divide the numerator 2 by the denominator 3 and add the result to the whole number 6:
If 1 arrangement weighs 6.666 pounds, the total weigth of 3 arrangements can be calculated by multiplying 6.666 pounds by 3: