Question

Consider the random variable D = R - B. That’s D for “difference.” If all 240 rolls show blue faces, then D = -240; if they all show red faces, then D = 240; otherwise D is somewhere in between. The random variable D is the sum of 240 draws at random with replacement from
1)[pick all that are correct]
...................................................................
red, red, blue, blue, green, green
red, red, blue, blue, 0, 0
1, 0, 0, 0, 0, 0
1, 1, 0, 0, 0, 0
1, 0, 0
0, 1, 0
1, -1, 0, 0, 0, 0
1, 1, -1, -1, 0, 0
1, -1, 0
....
2)Find E(D)
...
3)Find SE(D)

Please help