Question 1184541
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<pre>

    {{{t/4}}} + {{{t/5}}} = 1


Multiply both sides by 20.


    5t + 4t = 20

      9t    = 20

       t    = {{{20/9}}}  hours = 2 {{{2/9}}}  hours.    <U>ANSWER</U>
</pre>

Solved.