What are the upper and lower limits of the shaft represented by $$60{f_8}$$?

Use the following data:
Diameter $$60$$ lies in the diameter step of $$50-80$$ $$mm$$
Fundamental tolerance unit, $$i,$$ in $$\mu m = 0.45\,\,{D^{1/3}} + 0.001D,$$
where $$D$$ is the representative size in $$mm;$$ Tolerance value for $${\rm I}T8 = 25i,$$ Fundamental deviation for $$'‘f’'$$ shaft $$ = - 5.5{D^{0.41}}$$

Match the following

If the principal stresses in a plane stress problem are $${\sigma _1}$$ $$= 100$$ MPa, $${\sigma _2}$$ $$= 40$$ MPa, the magnitude of the maximum shear stress (in MPa) wil be

A solid shaft of diameter, $$d$$ and length, $$L$$ is fixed at both the ends. A torque, $${T_0}$$ is applied at a distance, $$L/4$$ from the left end as shown in the figure below.

The maximum shear stress in the shaft is