Please help me to answer completely the Required 1 of this exercise. Thank you.

Exercise 6-21 The Bellview Corporation, which sells a single commodity, show the following operating results for a 3-year period: Sales Cost of Sales Gross Profit Operating Expenses Net Income 2018 P4,500,000 2019 P6,000,000 2020 P6,200,000 2,925,000 4,080,000 4,216,000 P1,575,000 P1,920,000 P1,984,000 1,200,000 1,400,000 1,500,000 P375,000 P520,000 P484,000 The selling prices of the commodity sold were as follows: in 2018, P22.50; in 2019, P24.00; and in 2020, P25.00. REQUIRED: 1. Prepare a summary of the detailed changes in gross profit for 2019 and 2020 as compared with the year immediately preceding in terms of volume changes and price changes for both sales and costs.