Ni$2+$ is determined by back titration using Zn$2+$ at pH$=5\mathrm{.}5$ in the presence of xylene orange indicator. $25$ ml $0\mathrm{.}055283$M EDTA is added to $25$ ml Ni$2+$ solution. The excess EDTA is back titrated with $17\mathrm{.}61$ ml $0\mathrm{.}02299$ M Zn$2+.$

What is the Ni$2+$ concentration in the sample?