A regular triangular pyramid has a base and lateral faces that are congruent equilateral triangles. It has a lateral surface area of 81 square feet. What is the surface area of the regular triangular pyramid?

Pranav and molly are selling pies for a school fundraiser. customers can buy blueberry pies and pumpkin pies. pranav sold 6 blueberry pies and 4 pumpkin pies for a total of $106. molly sold 6 blueberry pies and 3 pumpkin pies for a total of $90. find the cost of each of one blueberry pie and one pumpkin pie