Answer:
The sample size required is at least 171
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
What sample size is required?
A samle size of at least n is required, in which n is found when 
So
Rouding up
The sample size required is at least 171
Answer:
let t = no of minutes when they are at the same altitude
:
52200 - 3300t = 2500t
52200 = 3300t + 2500t
52200 = 5800t
t = 52200/5800
t = 9 minutes they will be at the same altitude
:
The altitude:
9*2500 = 22500 ft
:
Check on other train
52200 - 9(3300) =
52200 - 29700 = 22500 ft
Answer:
Step-by-step explanation:
Subtract 7 from both sides.
Multiply both sides by v.
Multiply both sides by 1/(y - 7).
Answer:
3x + 9 + 4x + x = 8x + 9
Step-by-step explanation:
combine like terms
<h3>
Answer: 13,011.11 dollars</h3>
note: remember to take the comma out or ignore it. I put it in there to help make the number more readable
===========================================
Explanation:
Let x be the value of the sale in dollars.
x-1900 represents the leftover amount that is over 1900
eg: if x = 2200, then x-1900 = 2200-1900 = 300 is the the leftover amount
taking 9% of (x-1900) leads to the expression 0.09(x-1900) and this expression must be 1000 since this is the extra amount of money the salesman needs (he already has $1000 in base pay)
-------------
Solve for x
0.09(x-1900) = 1000
x-1900 = 1000/0.09
x-1900 = 11,111.11111 approximately
x = 11,111.11111 + 1900
x = 13011.1111
x = 13,011.11 rounding to the nearest cent
