MDU RESOURCES GROUP, INC. COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES AND COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS Twelve Months Year Ended Ended September 30, 2003 December 31, 2002 (In thousands of dollars) Earnings Available for Fixed Charges: Net Income (a) $175,376 $148,444 Income Taxes (b) 96,725 86,230 272,101 234,674 Rents (c) 8,938 8,156 Interest (d) 52,257 51,393 Total Earnings Available for Fixed Charges $333,296 $294,223 Preferred Dividend Requirements $ 735 $ 756 Ratio of Income Before Income Taxes to Net Income 155% 158% Preferred Dividend Factor on Pretax Basis 1,139 1,194 Fixed Charges (e) 66,265 59,549 Combined Fixed Charges and Preferred Stock Dividends $ 67,404 $ 60,743 Ratio of Earnings to Fixed Charges 5.0x 4.9x Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends 4.9x 4.8x (a) Net income excludes undistributed income (loss) for equity investee. (b) Includes income tax benefits of $4,821 associated with the cumulative effect of accounting change for the twelve months ended September 30, 2003. (c) Represents interest portion of rents estimated at 33 1/3%. (d) Represents interest, amortization of debt discount and expense on all indebtedness and amortization of interest capitalized, and excludes amortization of gains or losses on reacquired debt (which, under the Federal Energy Regulatory Commission Uniform System of Accounts, is classified as a reduction of, or increase in, interest expense in the Consolidated Statements of Income) and interest capitalized. (e) Represents rents (as defined above), interest, amortization of debt discount and expense on all indebtedness, and excludes amortization of gains or losses on reacquired debt (which, under the Federal Energy Regulatory Commission Uniform System of Accounts, is classified as a reduction of, or increase in, interest expense in the Consolidated Statements of Income).