There are 57 people in a certain community who belong to the local golf club, tennis club or both clubs. If twice as many people belong to the tennis club as belong to the golf club, what could be the number of people who belong to both clubs?  Choices:
A) 1) 4 B) 2) 7 C) 3) 17 D) 4) 21 E) 5) 27
x -&gt; Golf Club   2x -&gt; Tennis Club   y -&gt; both   x+2x-y = 51   3x - y =51   multiples of 3 greater than 51   60   63   66   69   72 - 21= 
<gadget id="calculator">72 - 21</gadget>
<output>51</output>
51   IMO (4) 21)
<result>D</result>
There are 57 people in a certain community who belong to the local golf club, tennis club or both clubs. If twice as many people belong to the tennis club as belong to the golf club, what could be the number of people who belong to both clubs?