Answer:
The sequence is arithmetic
we know that
In an arithmetic sequence, the difference between consecutive terms is always the same and is called common difference
In this problem we have
3,9,15,21,...
Let
a1=3, a2=9,a3=15,a4=21
a4-a3=21-15=6
a3-a2=15-9=6
a2-a1=9-3=6
The sequence is arithmetic
The common difference is equal to
Answer:
27
Step-by-step explanation:
Lets find the rate of selling:
Let v= the rate of selling, b = number of bottles of water, and t = time:
b over t gives us the
rate of selling:
3 hours is 60min * 3 = 180 mins, and since v=b/t, vt=b:
(0.15) * 180 = 27 bottles of water
Answer:
We need a sample size of least 119
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
The margin of error is:

95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
Sample size needed
At least n, in which n is found when 
We don't know the proportion, so we use
, which is when we would need the largest sample size.






Rounding up
We need a sample size of least 119