Question

a cupboard is filled with large no. of balls of 6different colors. you already have one ball of each color. if you r blind folded, how many balls do you need to draw to be sure of having 3 color matched pair of balls?

Answer 1

i think is one third of all the balls plus five
if these 6 color balls all have equal amount
1/3 of all the balls can have at least 2 color matched pair of balls.
let there are 6 kind of colors name a,b,c,d,e,f
if u r unlucky enough, maybe you pick 1/6 of all the balls only has the color of 'a'(it is possible in math)
that is to say, maybe you pick 1/3 of all the balls only has the color of 'a' and 'b'
then talk about 'plus five'
if u r unlucky enough, after you pick 1/3 of all the balls, u take all the color 'a' and 'b' away, and there are 4 kinds of color rest.
then ur unlucky enough, pick next four balls are all different color
the fifth one must pair with one of previous four. that is why 'plus five'

Answer 2

oh im sorry, i miss the sentence 'already have one ball of each color'
so the answer is one third of all the balls plus one