volume=length times width times height
this should be easy
a.
the volume of a box is 2.5 times 1 times 1 or 2.5 cubic meters
b.
number of boxes times volume per box=volume of container
number of boxes=volumecontainer/volumebox
find volumecontianer
volumecontainer=5 times 2 times 3=30 cubic meters
number of boxes=30/2.5
number of boxes=12
12 boxes needed to fill container
c.
box
1m=100cm
1m by 1m by 2.5m convert so (times everybody by 100)
100cm by 100cm by 250cm
multiply
2,500,000 cubic centimeters