There are 10 green, 10 red, 10 blue, and 10 yellow cards in a stack of 40 cards.

Question

What is the least number of cards a blindfolded person must draw from the stack to be sure to have at least 7 greem cards?

Answer 1

The answer is 28,

Ex.

g,r,b,y

g,r,b,y

g,r,b,y

g,r,b,y <---16

g,r,b,y

g,r,b,y

g,r,b,y <-- 28