Answer: 
Step-by-step explanation:
Given: A bag contains 2 black balls, 4 yellow balls and 4 white balls.
Event A is defined as drawing a white ball on the first draw.
Event B is defined as drawing a black ball on the second draw.
P(B|A) is expressed as the conditional probability of occurring B given that A.
i.e. it is the probability of happening B where A is already happended.
If a white ball is drawn at first, then the number of black ball(4) remains unchanged but the total number of balls (10) will become 9.

Then, 
Answer:
The last choice: log 25 Over log 8
Step-by-step explanation:
Because the change of base formula says:
log (subscript 8) of 25 = log (25) / log (8)
let log be the Common Log without subscripts
9,2.5,-4,-10.5,-17
Let's find the difference between two consecutive terms
2.5 - 9 = -6.5
-4 - 2.5 = -6.5
-10.5 - (-4) = -6.5
-17 -(-10.5) = -6.5
We can see that the common difference is -6.5
-6.5 is the common difference between successive terms in the sequence 9,2.5,-4,-10.5,-17
the common difference is negative because we subtract 6.5 to get the next term.
1/5 of 80 =16
16x4=64
this means he needs 16 more dollars
16/7.75=2.06451612903
this means that he has to work for two more hours.
hope this helps :)
As from the question,
x = 60°
πd = 12π
Using the Arc Length formula,
x/360° × πd
= 60°/360° × 12π
= 2π
Ans: B