GMAT prep notepad problem
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Hi, Here is my approach..
The note pads come in
2 sizes,
4 colors - B,G,Y and P
Packages has to be either a) 3 of same size and color, or b) 3 of same size and different color.
Since the packages are of all same size,we can do this problem as one size (say small) and then multiply by 2(to include larger size)
Then a)no. of ways of choosing all 3 of same color = 4
b) no. of ways of choosing 3 different colors = 4C3 (since order does not matter) =>4
Number of small size packages = 4+4=8.
Similarly number of large size packages = 8.
Total =8+8=16. For me ,splitting the problem made it easier..
The note pads come in
2 sizes,
4 colors - B,G,Y and P
Packages has to be either a) 3 of same size and color, or b) 3 of same size and different color.
Since the packages are of all same size,we can do this problem as one size (say small) and then multiply by 2(to include larger size)
Then a)no. of ways of choosing all 3 of same color = 4
b) no. of ways of choosing 3 different colors = 4C3 (since order does not matter) =>4
Number of small size packages = 4+4=8.
Similarly number of large size packages = 8.
Total =8+8=16. For me ,splitting the problem made it easier..