can you solve this question for me ?

4. Barb has a hot-dog stand near the ferry terminal for Centre Island. She pays $500 per month as rent and $3000 per month in wages for the hired help. Variable costs per hot dog come out to be $1.30 and she sells each hotdog for $3.00. In summer months, she is able to sell 4500 hotdogs in a month. Recently, another hot dog vendor opened his stand across the street. To attract and retain her customers, she added a free soda can which increased her variable costs by 20 cents. To make things worse, the rent was also increased by 15%. What is the change in her monthly net income due to these recent changes. Assume that the monthly sale figures remain at 4500 units