BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Marbles

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 65
Joined: Fri Jul 24, 2009 11:47 am
Thanked: 5 times

Marbles

by rish » Mon Aug 03, 2009 11:16 am
A student is asked to pick marbles from a bag that contains 18 marbles. Eight marbles are red, 4 are green, and 6 are black. What is the minimum number of marbles that a blindfolded student would have to draw from the bag to be certain of having at least three marbles of the same color?

A) 5

B) 6

C) 7

D) 13

E) 14
Top
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 74
Joined: Fri Jul 31, 2009 11:38 am
Thanked: 4 times
Followed by:1 members

Re: Marbles

by quant-master » Mon Aug 03, 2009 11:21 am
rish wrote:A student is asked to pick marbles from a bag that contains 18 marbles. Eight marbles are red, 4 are green, and 6 are black. What is the minimum number of marbles that a blindfolded student would have to draw from the bag to be certain of having at least three marbles of the same color?

A) 5

B) 6

C) 7

D) 13

E) 14
Let's consider the worst case.

The student should have 3 marbles of the same colour, after 6 draws the worst case will be 2 marbles of each colour. When he draws the next ball, no matter what the colour is, he will have 3 balls of same colour for sure.

Hence C

Thanks,
Quant-Master
https://gmat-quants.blocked - My Blog Updated almost daily with new quant fundas. Find collection of quants question in my blog
Top
Post new topic Post Reply
• Page 1 of 1