There are 4 white and 5 red (indistinguishable) balls in a bag. Suppose you draw one ballout at a time without replacement and stop when you have drawn all the white (4 white) orall the red (5 red) balls. What is the probability that the last ball you drawn was a whiteball?

5/9

Step-by-step explanation:

What we have in this question are four white balls and 5 red balls.

This is the sample space

[(4w,0R) (4w,1R)(4w,2R)(4w,3R)(4w,4R)(0w,5R)(1w,5R)(2w,5R)

So we have 9 possible sets of events

The event number with the last ball being white = 5

Probability of the last ball drawn being white = 5/9

= 0.56

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