River C is 400 miles longer than River D. If the sum of their lengths is 5,590 miles, what is the length of each river?​

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Afarm that has 4 x 10^2 acres has 1.2 x 10^5 cattle. what is the average number of cattle per acre? write the answer in scientific notation. answere asap

Ametal rod needs to be 9 feet and 5.5 inches in length. the sections of the poles being used are each 1 foot and 10.5 inches long. how many 1ft 10.5in sections would be needed to complete the 9ft 5.5in metal rod? and how many inches of material will be left?