Q$4$: $(10$ Mark$)$

A material is subjected to two normal compressive stresses of $-0\mathrm{.}25$ Y and $-0\mathrm{.}5$ Y acting and $y$ direction respectively. What tensile stress applied in the z direction would cause and shear octahedral stress according to Von Mises and Tresca criterions. ${}_y=$YMPa