Answer:
150+12x=630
Step-by-step explanation:
The x represents the amount of months and it is multiplied by 12 because each month costs 12$. 150 have to be paid up front and this added to the monthly fee is equal to 630$
Answer:
21
Step-by-step explanation:
Using<em> Simple Random Sampling</em>, we can estimate the sample size by the formula
where
n = sample size
Z = the z-score corresponding to the confidence level 99.5%
S = the assumed standard deviation = 3 seconds
e = margin of error = 2 seconds
<em>It is worth noticing that the higher the confidence level, the larger the sample should be.
</em>
The z-score corresponding to a confidence level of 99.5% can be obtained either with a table or the computer and equals
Z = 3.023
Replacing the values in our formula
So the size of the sample should be at least 21.
139b + 1.29b = 50.73
2.49m + 2.69m = 51.63
X= -4y let this be equation 1
x+5y=2 let this be equation 2
substitute equation 1 in 2
-4y + 5y = 2
y=2
substitute the value of y in equation 1
x= -4y
x= -4(2)
x= -8