When $10 \mathrm{mL}$ of an aqueous solution of ${\mathrm{Fe}}^{2+}$ ions was titrated in the presence of dil ${\mathrm{H}}_2{\mathrm{SO}}_4$ using diphenylamine indicator, $15 \mathrm{mL}$ of $0.02 \mathrm{M}$ solution of ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ was required to get the end point. The molarity of the solution containing ${\mathrm{Fe}}^{2+}$ ions is $\mathrm{x}\times {10}^{-2} \mathrm{M}$. The value of $\mathrm{x}$ is ______. (Nearest integer)

Hence, the correct answer is 18.