Answer:
Following are the solution to the given question:
Step-by-step explanation:
Confidence Interval for both the percentage of all x-ray machines
p = the machinery's share is not working:

Lower
Confidence interval = p - error margin
Upper
Confidence Interval = p + error margin
So,
Confidence Interval 
Answer:
The sum of 8 geometric sequence is 959780
Step-by-step explanation:
We are given
this sequence is geometric
-4 , 24 , -144
First term is -4
so, 
now, we can find common ratio

we can use formula

n=8
now, we can plug values

now, we can simplify it
and we get

Answer:
We have been given an equation 
We will factorize it by middle term splitting.
Step 1: 
Taking common factors out by clubing first two terms ad last two terms
Step 2: 
Step 3: 
Equating both above factors to zero as:
Step 4: 
And
.
The answer to this is
x=8
<span>It will take 20 minutes. The fridge needs to cool down by 90-50=40degrees. The fridge cools at 2 degrees per minute, i.e. 40/2=20 minutes total.</span>