Question 109188
Jon spent 1/3 of his study time doing math homework and 2/7  preparing for a history exam. What fraction of his study time remains?
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Time he has used: (1/3)+(2/7) = 7/21 + 6/21 = 13/21
Time he has left: (21/21)-(13/21) = 8/21
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Cheers,
Stan H.