Hi, My code is ion cocos2D. I have written code for generating the bullets from the enemy gun for every 0.3seconds. The enemySprite is in right side of the screen in (land scape mode) at winSize.height/2. the bullet starts from the same point and reach the player's end. I used rand() to generate y-coordinate for the bullet to hit on player side. Now, if the bullet bounded rectangle meets the player bounded rectangle the enemy won. If it misses enemy shoots again after 0.3 seconds. Every thing is fine up to here for me. But I have 10 enemies and each have accuracy of hitting player of probabilities ranging from 0.80 to 1.0. First enemy probability is .80 and 10 enemy's is 1.0. How can I adjust the probability for enemy such that it runs according to its probability. Player also hits the enemy.