Final answer:
Carla's total commission for the month is $6,602.21.
Step-by-step explanation:
To calculate Carla's total commission for the month, we need to calculate the commission for each range of sales and then add them up.
1. Commission for the first $20,000 at 3.4%:
20,000 * 3.4% = $680
2. Commission for the next $60,000 at 5%:
60,000 * 5% = $3,000
3. Commission for the remaining sales over $80,000 at 5.7%:
(135,643 - 80,000) * 5.7% = $2,922.21
Now, we can add up the individual commissions:
$680 + $3,000 + $2,922.21 = $6,602.21