Final answer:
Melissa can deduct $2,630 as business expenses.
Step-by-step explanation:
To determine the amount of business expenses Melissa can deduct, we need to add up all her expenses during the business conference.
The expenses she can deduct include the registration fee of $405, lodging expenses of $360 per night for three nights (totaling $1,080), meal expenses of $280, and cab fare of $240. We also need to include the cost of airfare, which is $625.
The total deductible expenses are $405 + $1,080 + $280 + $240 + $625 = $2,630.
Therefore, Melissa can deduct $2,630 as business expenses.