For this you will have to make a tree diagram 
it will be so much easier although there is a way to do it
probability of getting heads is = 1/2 there for 10 tosses its (1/20)^10
        
             
        
        
        
Im guessing by my predicition that it will be 0.11 that will continue
        
             
        
        
        
Answer:
If it's where they can get to the building I think it's 15
Step-by-step explanation:
Cause 10 plus 5 and if that can reach where they are able to get in I'd assume it would be 15
I'm not a genius or anything so don't rely on my answer
 
        
             
        
        
        
Answer:
a) To determine the minimum sample size we need to use the formula shown in the picture 1. 
E is the margin of error, which is the distance from the limits to the middle (the mean) of the confidence interval. This means that we have to divide the range of the interval by 2 to find this distance. 
E = 0.5/2 = 0.25
Now we apply the formula
n = (1.645*0.80/0.25)^2 = 27.7 = 28
The minimum sample size would be 28.
b) To answer the question we are going to make a 90% confidence interval. The formula is: 
(μ - E, μ + E)
μ is the mean which is 127. The formula for E is shown in the picture. 
E = 0.80*1.645/√8 = 0.47
(126.5, 127.5) 
This means that the true mean is going to be contained in this interval 90% of the time. This is why it doesn't seem possible that the population mean is exactly 128. 
 
        
             
        
        
        
The answer is 
B. 13ab
5ab+9ab-ab
=(5ab+9ab)-ab
14ab-ab
=13ab
Hope it helped : )