The outstanding stock in Red, blue and Green Corporation, each of which has only one class of stock, is owned by the following unrelated individuals:

	Corporations
shareholders	red	blue	green
marrin	20%	10%	30%
murray	10%	50%	20%
moses	50%	30%	35%

a. Determine whether Red, Blue and green Corporations constitute a brother-sister controlled group

b. Assume that Murray does not own stock in any of the corporations. Would a brothersister controlled group exist? Explain