# Minimum number of marbles to have taken one of each colour.

• Feb 10th 2011, 11:52 PM
Minimum number of marbles to have taken one of each colour.
Q9: In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green
marbles. How many will he have to take out of his pocket to ensure
that he has taken out at least one of each color?
A. 11
B. 7
C. 8
D. 9
how??
• Feb 11th 2011, 12:07 AM
earboth
Quote:

Q9: In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green
marbles. How many will he have to take out of his pocket to ensure
that he has taken out at least one of each color?
A. 11
B. 7
C. 8
D. 9
how??

Consider the case that he took out the blue and the green marbles first (= 8 marbles). Then the next one must be a red one and he then has gotten all three colours.
• Feb 11th 2011, 12:09 AM
pickslides
Well if the first 3 the took were red and the next 4 he took were blue, that would be seven, so the next one would have to be green and he would then have one of each colour.

But if he took 4 blue then 4 green the next one would be red and that would make 9.

The idea here is to add the 2 biggest numbers so there is no chance you can miss a colour.