GMAT TIGER wrote:
Try this one from me.
In the jar there are white and black marbles (W>0 and B>0). How many black marbles are there?
(1) There are total 101 marbles in the jar.
(2) From any two marbles from the jar at least one is white.
Again, please share your way of thinking, difficulty level and quality.
Explanation of the answer to follow.
C. If white marbles were 100 and 1 Black marble, then only you get at least 1/2 while drawing 2 marbles from the jar. But you do not get answer (no. of black and white marbles) until you mix 1 and 2.
GMAT TIGER I didn't get the reasoning of your answer can you please specify. Anyway what's your answer, how many black marbles are there? C is incorrect.
Maybe you misunderstood the statements, or I stated them ambiguously
I guess I overlooked - thought white for black. It is B.
Given that: w>0 and b>0.
(1) Total = 101 tells nothing about individusl msrbles.
(2) If any two marbles from the jar are drawn, at least one is a white. That means black cannot be more than 1. so Black = 1 irrespective of whites.
Another good one. Are you gmat instructer/question writer?