Answer:
Mean track length for this rock specimen is between 10.463 and 13.537
Step-by-step explanation:
99% confidence interval for the mean track length for rock specimen can be calculated using the formula:
M±
where
- M is the average track length (12 μm) in the report
- t is the two tailed t-score in 99% confidence interval (2.977)
- s is the standard deviation of track lengths in the report (2 μm)
- N is the total number of tracks (15)
putting these numbers in the formula, we get confidence interval in 99% confidence as:
12±
=12±1.537
Therefore, mean track length for this rock specimen is between 10.463 and 13.537
41 years old as 47 take away 6 makes 41
-4(x + 1) + 7x = 8
-4x - 4 + 7x = 8
3x - 4 = 8
3x = 8 + 4
3x = 12
x = 12/3
x = 4 <===
Let the event 
The the probability of the events


The conditional probability

Answer:
You can spend 4 days in Los Angeles and 3 days in San Francisco.
Step-by-step explanation:
From the information given, you can write the following equations:
x+y=7 (1)
275x+400y=2,300 (2), where:
x is the number of days to visit Los Angeles
y is the number of days to visit San Francisco
First, you can solve for x in (1):
x=7-y (3)
Now, you can replace (3) in (2):
275(7-y)+400y=2,300
1,925-275y+400y=2,300
125y=2,300-1,925
125y=375
y=375/125
y=3
Finally, you can replace the value of y in (3) to find x:
x=7-3
y=4
According to this, the answer is that you can spend 4 days in Los Angeles and 3 days in San Francisco.