Verified Answer :

  1. find volume
    V=LWH
    V=251314
    V=4550
    each covers 1000
    how many will cover the whole thing?
    we can't put 4 becuase that leaves 550 uncovered
    add another


    5 is answer (it is too much , but at leas not too little) answer is D




    2.
    V=LWH
    V=6410
    V=240

    answer is D






    3.  count how many are there, don't forget the hidden ones
    13 cubes
    volume=legnth tiems width times height
    cubes so
    v=side^3
    side=3
    3^3=27
    13 cubes
    13*27=351 in^3


    challenge (this is meant to challenge you, not for you to ask people, but I will solve anyway, robbin you of experience)

    V=LWH
    V=5880
    H=30
    5880=LW30
    divide both sides by 30
    196=LW
    they have square bases so L=W
    196=L^2
    sqrt both sides
    14=L=W
    the side legnth is 14in