There are 30 pieces of 4 different colours but same size balls in a bag.

Asmo is asked to take out balls from the bag with closed eyes. To guarantee
the balls taken are not less than 5 same colour balls, at least how many balls should be taken out from the bag?

1 answer

Suppose 4 of each color were drawn. That makes 16 balls.

The 17th ball would have to be the 5th of one of the colors.