An unknown sample of Ni$2+$ gave a current of $2\mathrm{.}36\backslash$mu A in an electrochemical analysis.

When $0\mathrm{.}500$ mL of solution containing $0\mathrm{.}0287$ M Ni$2+$ was added to $25\mathrm{.}0$ mL of unknown,

the current increased to $3\mathrm{.}79\backslash$mu A$.$ Find $[$Ni$2+]$ in the original unknown sample.