Assume that $$100$$ candidate took the examination.
In that $$72\%$$ of them are passed $$=72$$ candidates
In that failed candidates $$=(100-72)=28$$
Number of candidates if $$28$$ of them failed $$=100$$
Number of candidates if $$392$$ of them failed $$=(100/28)\times 392$$
$$=1400$$
$$\therefore$$ the total number of examinees is $$1400$$