IMPA Portal Videos - Sixth Year Exercises OBMEP 2021 - Level 3 Exercise 1: The little black houses in the comb below are full of honey and the little white houses are empty. How many empty houses must the bees still fill with honey so that the number of empty houses is equal to the number of houses with honey?
OBMEP 2021: Second Phase - Level 1 Exercise 1 Mariana has a set of 15 pins, with 5 black, 5 white and 5 gray. Pins of the same color are worth the same number of points. The score obtained in a play is the sum of the points of the pins corresponding to the knocked down pins. In one play, Mariana scored 10 points by knocking down two black pegs. In another play, she scored 12 points by knocking down a black and a white peg. In a third move, Mariana scored 55 points by knocking down three black, one white and three gray pins.