Answer: the amount paid for the paddleboats is $1913.08 (rounded to two decimal places).
Step-by-step explanation:
To calculate the amount paid for the paddleboats by Tyler Creek Campground, we need to apply the series discounts and the terms provided.
First, let's apply the series discounts of 8%, 12%, and 15% to the list price of $2780. Series discounts are applied sequentially, one after the other.
1.
Apply the first discount of 8%:
$\text{Discounted Price}_1 = 2780 \times (1 - 0.08)$
$\text{Discounted Price}_1 = 2780 \times 0.92$
$\text{Discounted Price}_1 = 2557.60$
2.
Apply the second discount of 12% to the new price:
$\text{Discounted Price}_2 = 2557.60 \times (1 - 0.12)$
$\text{Discounted Price}_2 = 2557.60 \times 0.88$
$\text{Discounted Price}_2 = 2250.688$
3.
Apply the third discount of 15% to the new price:
$\text{Discounted Price}_3 = 2250.688 \times (1 - 0.15)$
$\text{Discounted Price}_3 = 2250.688 \times 0.85$
$\text{Discounted Price}_3 = 1913.0848$
Now, we have the discounted price after applying the series discounts. The terms "3/10-10 extra" mean that there is an additional 3% discount if the invoice is paid within 10 days, but since the campground paid within 20 days, this additional discount does not apply.