Mike took clothes to the cleaners three times last month. First, he brought 4 shirts and 2 pairs of slacks and paid $17.94. Then he brought 7shirts, 4 pairs of slacks, and 2 sports coats and paid $47.37. Finally, he brought 4 shirts and 2 sports coats and paid $23.94. How much was he charged for each shirt, each pair of slack, and each sports coat?