Question 1128848
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Let t be the time (in hours) he spent running.

Then the time he swam was (7.5 - t) hours.


The total distance equation then is


    9*t+ 2*(7.5-t) = 46.5


    9t + 15 - 2t = 46.5

    7t = 46.5 - 15 = 31.5

    t = {{{31.5/7}}} = 4.5.


<U>Answer</U>.  He ran for 4.5 hours and swam for 7.5-4.5 = 3 hours.


<U>Check</U>.   9*4.5 + 2*3 = 46.5 kilometers.    ! Correct !
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Solved.