Answer:
a.
b.
c.
Step-by-step explanation:
a. void ratio is provided by the formula:

where ,
= volume of voids
= volume of solid grains
for loose sand, the void space =

= 1
b. void ratio after static load = 0.1/(480)/ (480)
= 0.1
c. void ratio after vibration = [480- ( 0.1 * 480) ]/ 480
= 0.9