Sam and Dennys ice cream shop charges $2.50 for a cone. Variable expenses are $0.80 per cone, and fixed costs total $3,200 per month. A sweetheart promotion is being planned for the second week of February. During this week, a person buying a cone at the regular price would receive a free cone for a friend. It is estimated that 750 additional cones would be sold and that 950 cones would be given away. Advertising costs for the promotion would be $350.

Required:
a.	Calculate the effect of the promotion on operating income for the second week of February? I do know the operating income will increase but by how much? What is the equation? (the posted question is not answered properly)