Boston railroad decided to use the high-low method and operating data from the past six months to estimate the fixed and variable components of transportation costs. the activity base used by boston railroad is a measure of railroad operating activity, termed "gross-ton miles," which is the total number of tons multiplied by the miles moved. transportation costs gross-ton milesjanuary $1,776,000 560,000february 2,700,000 1,000,000march 1,650,000 500,000april 1,860,000 600,000may 1,440,000 400,000june 1,566,000 460,000determine the variable cost per gross-ton mile and the total fixed cost.