There is a bag filled with 5 blue, 6 red and 2 green marbles. A marble is taken at random from the bag, the colour is noted and then it is not replaced. Another marble is taken at random. What is the probability of getting 2 blues?

Step-by-step explanation:

Total marbles = 5  + 6 + 2 = 13

P( getting blue ball from first draw) = 5/13

The marble is not replaced. So, Now total marbles will be 12 & number blue marbles will be 4

P( getting blue ball from second draw) = 4/12 = 1/3

P(getting two blues) =

                                  = 5/39

the mistake in the pattern is that :

b. the decimal point was moved one too many place values each time

the correct pattern could be made by :

b. moving the decimal point to the right the same numbers of place values as the exponents