Question

Create an expression to find the time for the given distance and rate, and find the value of the expression. 

Answer 1

Note the equation/formula:
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         d * r = t  ;
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  in which:  
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        d = distance = 84 ft.
        r  = rate = 12 ft / sec
        t  = time = ?
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To find the "time" we can rearrange the equation:
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       d = r * t  ;   
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   Divide EACH SIDE of the equation by "r" ;  to isolation "t" on one side of the equation; to create an expression to find the time for the given distance and rate; which we will then do by plugging in our given values for "d" (distance) and "r" (rate) ;
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     d / r = (r * t) / r ;  
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 to get :   d / r = t ; 
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         ↔   t = d / r  ;
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Now, plug in our given values for "d" and "r" ; to solve for "t" ;
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        →    t = 84 ft / (12 ft / sec) ; 
   
                  =  84 ft   ÷    ;
    
                  =  84 ft  *   ;
  
                  =  {   }  sec. ; 
  
                    →   t    =   7 sec.   {that is;  "7 seconds" }