A greenhouse contained both 6-inch high geraniums and 3 inch high geraniums. The 6-inch high geraniums were taken out of the greenhouse in early spring and grew at a rate of 1 inch per week. The 3 inch high geraniums remained in the greenhouse and grew at a rate of 1 (1/2) inches per week. After the 6-inch high geraniums were taken outside, in how many weeks were both groups of geraniums the same height.