crackgmat007 wrote:Can someone explain this in more detail? Tx.
Lets take a 2 step approach.
A) 3 note pads of the same size and same color.
We have to 2 choices for size and 4 choices for color. -> 2 * 4 = 8
B) 3 note pads of the same size and of 3 different colors
Since we have to choose 3 DIFFERENT colors, we can apply the formula 4choose3 -> 4! / (3! * 1!) = 4.
Now for each of these color combinations we have the option of 2 sizes...hence 4 * 2 = 8.
From A and B, we get 8 + 8 = 16.
** For part B **
It is important to use 4choose2 ...coz if we think of it as 4 choices for each spot then we get 4 * 4 * 4....we would be overcounting in this case as we can get the possibility of 2 pads being the same color (Red, Red, Blue) which cannot be the case.... to eliminate this if we consider 4 choices for the 1 one...and 3 choices for the second one...we wuold use 4 * 3 * 2 as possible solutions but then we are saying that order does matter so (Red, Green, Blue) is different from (Blue, Green Red) or (Green, Red, Blue).
Hope this helps.
Attempt 1: 710, 92% (Q 42, 63%; V 44, 97%)
Attempt 2: Coming soon!
