manalq8 wrote:
Two consultants can type up a report in 12.5 hours and edit it in 7.5 hours. If Mary needs 30 hours to type the report and Jim needs 12 hours to edit it alone, how many hours will it take if Jim types the report and Mary edits it immediately after he is done?
A. 41.4
B. 34.1
C. 13.4
D. 12.4
E. 10.8
We can let Jim’s typing time = j, and thus his rate = 1/j. Since Mary needs 30 hours to type the report alone, Mary’s typing rate is 1/30. Since together they can type the report in 12.5 hours,
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