Answer:
5.744
Step-by-step explanation:
the answer is 5.744 hope it helps!
Answer:

Step-by-step explanation:
Probability refers to chance of happening of some event.
Conditional probability is the probability of an event A, given that another event B has already occurred.
denote the two boxes.
In box
:
No. of black balls = 1
No. of white balls = 1
In box
:
No. of black balls = 2
No. of white balls = 1
Let B, W denote black and white marble.
So, probability that either of the boxes
is chosen is 
Probability that a black ball is chosen from box
= 
Probability that a black ball is chosen from box 
To find:probability that the marble is black
Solution:
Probability that the marble is black = 
So when you change the mixed numbers into improper fractions, they become 85/4 and 74/4. Your new problem is 85/4-74/4. Basically 85-74. That equals 9. So the improper fraction answer is 9/4. We now make that back into a mixed number, creating 2 1/4, or A.