There are some pigeons and hares in a zoo. If heads are counted, there are 200. If legs are counted, there are 680. The number of hares in the zoo is?	Choose one:
A) 90 B) 99 C) 77 D) 140 E) 221
200*2= 
<gadget id="calculator">200*2</gadget>
<output>400</output>
400   680   -----   280   1----2   ?----280=140   Answer:140
<result>D</result>
There are some pigeons and hares in a zoo. If heads are counted, there are 200. If legs are counted, there are 680. The number of hares in the zoo is?