rey.fernandez wrote:I assume there was a typo in your post... and that there are 12 yellow pills, not 132.
That said, one way to approach this problem is to go through the answer choices, starting with the smallest and working your way up, imagining the worst case scenario.
A: 12 is not enough, since it's possible that all 12 could be yellow
B: 17 could be 12 yellow, 5 red... not enough
C: 18 could be 12 yellow, 6 red... not enough
D: 23 could be 12 yellow, 10 red, 1 blue... not enough
E: 25, that's gotta be it by elimination (12 yellow, 10 red, 3 blue)
Great approach!
We also could have predicted the answer.
In this type of question, we always want to consider worst case scenarios. In other words, what could happen to stop us from getting 3 of each colour?
Well, we could start by picking all 12 yellow pills. Then, if we got unlucky, we'd pick all 10 blue pills. Now there's nothing left but red, so the next 3 have to be red pills.
So, 12 + 10 + 3 = 25.
