Charlie Stork rented a truck for his business on two previous occasions. Since he will soon be renting a truck again, he would like to analyze his bills and determine how the rental fee is calculated. His two bills for truck rental show that on September $1,$ he drove $1,000$ miles and the bill was $$1,500,$ and on December $5,$ he drove $600$ miles and the bill was $$1,380.$

Required

Complete the spreadsheet below to calculate the variable and fixed costs of this mixed cost that will allow Mr$.$ Stork to predict the cost if he drives the truck $700$ miles.