Madiha Yousaf on Nearpeer MDCAT Common Room

Sir, when I solve MCQs from the practice zone, like if I first choose 15 MCQs, then later when I select a new set of 15, about 10 of them are the same as before and only 2–3 are different. Why does this happen? Even if I got some wrong earlier, it was only one or two..so why do the same questions repeat?