Short Answer: 150
Remark
You have to use two facts.
1. The central angle = 2 * the angle at B
2. The central angle = the arc angle.
Given
angle at B = 75 degrees.
Calculate the central angle
Central angle = 2 * angle at B
Central angle = 2 * 75
Central angle = 150
Conclusion
The arc angle = Central angle
The arc angle = 150 degrees.
Answer:
Step-by-step explanation:
When the first draw is done there are 9 red balls in a sample size of 21. So there probability of drawing a red ball will be 
When the second draw is done, there will be 12 yellow balls in a sample size of 20 since the first ball will not have been replaced into the bag. So the chance of someone drawing the second ball in the second draw is 
The probability of them happening in this order is the product of both probabilities:
Answer:
P(C4) = 0.0711
Step-by-step explanation:
consider the first draw = 15/23 since it cannot be a blue ball
The second draw = 21/29 since 6 more red balls will be added after the draw since a blue ball cannot be drawn
the third draw = 27/35 since 6 more red balls will be added after each draw since a blue ball cannot be drawn
therefore the total number of red balls will be = 15 + 6 + 6 + 6 = 33 red balls after the 4th draw. the total ball now in the urn= 33 red + 4 blue = 41
Hence the probability of drawing a blue ball at the fourth draw after drawing red balls at the previous attempts = 8/41
P(C4) = P ( fourth ball is blue ) * P( first ball red)*P(second ball red) *P(third ball red )
= (8/41) * (15/23) * (21/29)* (27/35) = 0.0711
