There is a bag filled with 6 blue and 5 red marbles.A marble is taken at random from the bag, the colour is noted and then it is replaced. Another marble is taken at random. What is the probability of getting at least 1 red?
1st red 2nd red
1 st red 2nd other
1 other 2nd red are the possibles
6/11 * 6/11 + 6/11 * 5/11 + 5/11 * 6/11 = ( 36 + 30 + 30)/121 = 96 / 121 ( not positive)