Question 1135650
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Let t be how long it take you to get to the class (in minutes; the unknown that the problem asks to find).


The distance your roommate walked was 3 mph * 8 minutes = {{{3*(8/60)}}} miles.


The distance you walk is  5 mph * t minutes = {{{5*(t/60)}}} miles.



    Did you noticed that I converted each time from minutes to hours ?



The two distances are the same, so you have this equation


    {{{3*(8/60)}}} = {{{5*(t/60)}}}


to find "t".  First, cancel the factor 60 in both denominators.  You will get then


     3*8 = 5*t.


From this equation,  t = {{{(3*8)/5}}} minutes = {{{24/5}}} minutes = {{{4}}}{{{4/5}}} minutes = 4 minutes and 48 seconds.   <U>ANSWER</U>
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Solved.