 
<translate> Wanda ya ci nasara a shekarar da ta gabata ya ci hamburgers 21 domin 84 / 4 = 21. Tana bukatar ta ci hamburgers 22 domin 21 + 1 = 22. Saboda haka, amsar ita ce 22. <eng> Last year's winner ate 21 hamburgers because 84 / 4 = 21. She needs to eat 22 hamburgers because 21 + 1 = 22.
Therefore, the answer is 22. 