$5\mathrm{.}8$ A sand cone test was conducted for quality control dur$-$

ing the compaction of sandy clay. The data are as follows.

Calibration to find dry unit weight of the

standard sand

a$)$ Determine the dry unit weight of standard sand.

b$)$ Determine the volume of the sand cone.

c$)$ Determine the in$-$situ dry unit weight of the sandy clay.