text: This is simple algebra.  The rate thing 100 pgs / hr is a number as much as any number.  If we say X is the rate Marge types then Homer types at 2 * X and your equation is\n\n100 pgs/ 3 hrs = (2 * X) + X = 3 * X\n\nsolving for X we get Marge typing at 11.11 pgs/hr and Homer typing at 22.22 pgs/hr - So Marge will take 9 hours to do 100 pages on her own and Homer 3 hours.