How many different seven person committees can be formed each containing three female members from an available set of 20 females and four male members from an available set of 30 males?

The answer to this question is: 20*19*18*30*29*28*27=4,498,804,800 different sever person committees. For the first position there are 20 different women available. For the second position 20-1=19 different women. For the third only 18 women. For the fourth through seventh position there are 30 to 27 different men available. One is then to multiply each of those seven numbers with each other as above to get the correct answer.