Aset of positive integers {1, 2 , 3 , 4, 5 , 6 , 7 , 8 , 9} is used to form a pack of nine cards. each card displays one positive integer without repetition from this set. grace wishes to select four cards at random from this pack of nine cards. (a) find the number of selections grace could make if the largest integer drawn among the four cards is either a 5, a 6 or a 7.

If the largest integer drawn among the four cards is 5, then that means that 3 of the cards drawn are from the set {1, 2, 3, 4}. The number of ways of selecting 3 cards from 4 cards is given by:



If the largest integer drawn among the four cards is 6, then that means that 3 of the cards drawn are from the set {1, 2, 3, 4, 5}. The number of ways of selecting 3 cards from 5 cards is given by:



If the largest integer drawn among the four cards is 7, then that means that 3 of the cards drawn are from the set {1, 2, 3, 4, 5, 6}. The number of ways of selecting 3 cards from 6 cards is given by:



Therefore, the number of selections grace could make if the largest integer drawn among the four cards is either a 5, a 6 or a 7 is given by 4 + 10 + 20 = 34 selections.

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm