Answer:
A normal distribution or z-test is used to construct a confidence interval.
Step-by-step explanation:
We are given the following in the question:
Sample mean, 
= $3120
Sample size, n = 40
Population standard deviation, σ = $677
The distribution of earnings of college is a normal distribution.
Conditions:
- Since we are given the population standard deviation and the the sample size is also greater than 30.
Conclusion:
Thus, we use a normal distribution or z-test to construct a confidence interval.
Step-by-step explanation:
2x+3(3x+8)=13 y=3x+8
2x+9x+24=13 y=3(-1)+8
11x+24=13 y= -3+8 =8-3
11x=13-24 y=5
11x/11= -11/11
x= -1
Let 
represent the depth of the miner and equipments elevator, respectively. We know that equipment elevator descends with a velocity of 
feet per second, and the miners one descends with a velocity of 
feet per second.
If we start counting time (
) when the equipment elevator begins to descend, after 
seconds its depth will be
On the other hand, the miner elevator follows the same rule, but we have to use its velocity, and remember that it starts with a delay of thirty seconds:
Now, we have to wait the 30 seconds of delay, and then another 14 seconds. This means that we want to know the positions of both elevators when 
. Let's plug this value into the two equations:
So, the equipment elevator is 176 feet deep, and the miner elevator is 210 feet deep, and thus this is the deeper one.
