Hypothesis Tests · Hard problem

A two-sided $z$ test of $H_0: \mu = 50$ at level $\alpha = 0.05$ uses the critical value $z^* = \dfrac{49}{25}$. A sample of $36$ (population standard deviation $8$) gives $\bar x = \dfrac{140}{3}$. Is $H_0$ rejected? Answer reject or fail to reject.