Z Lemon Inc. is a women's shoe retailer. On February 1, 2022, the company purchased 500 pairs of "Angel" model shoes for $20 per pair. On March 3, the company purchased 700 pairs of the newly released "Bella" model shoes for $30 per pair. The Bella model's arrival caused the selling price of the Angel model shoes to drop from $70 to $60 per pair as the Bella model sells for $90 for each pair. On March 30, Lemon sold 120 pairs of the Bella model shoes. What is the gross profit on the sale of Bella shoes?