Which of the following is not equivalent to the formula d = rt?

The answer is:  [B]:  " r = dt " .

Explanation:

Let us consider the answer choices given:

The formula is:  d = rt ; (that is: "d = r * t ") .
 
Side note:  In practice, this formula stands for: " distance = rate * time " .

Consider "choice [A]:  d/r = t ;  This is true; 

 Given: d = rt ;  
   
          d/r = rt/ r ;  d/r = t .  True.

Consider "Choice [B]:  r = dt . 
 
          Given:  d = rt ;   r = d/t ; {not: " r = dt " }; so this answer seems correct!

Consider "Choice [C]:  d/t = r ;  
 
As shown directly above (that is, considering "Choice B"); r = d/t ; ↔ d/t = r; 
which is true.

Consider "Choice [D]:  d / rt = 1 ; 

Given:  d = rt ;   d/rt = rt/rt ;  d/rt = 1 ; since (rt/rt =1); so this is true.

So, Answer choice: [B]:  " r = dt " ; is the correct answer!