There are 18 yellow and more white and red balls in an urn. How many white and how many red balls are in the urn if the probability of drawing a white or a red ball is $1 / 15$ less than the probability of drawing a white or a yellow ball, and the probability of drawing a red or a yellow ball is $10 \%$ greater than the probability of drawing a white or a yellow ball?

(For the example, see the article 》Elements of Probability Theory《 in this issue.)