Answer:
a) We need a sample size of at least 3109.
b) We need a sample size of at least 4145.
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:
99% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
(a) he uses a previous estimate of 25%?
we need a sample of size at least n.
n is found when 
. So
We need a sample size of at least 3109.
(b) he does not use any prior estimates?
When we do not use any prior estimate, we use 
So
Rounding up
We need a sample size of at least 4145.
Half of the thing is cut off
Let m the tens digit and n the ones
the Original number is 10m+n
7(m+n) =10m+n
7m+7n=10m+n
6n=3m
Reversing the number 10n+m
10n+m=18+n+m
9n=18
n=2
6n=3m
6(2)=3m
3m=12
m=4
the number is 10m+n=10(4)+2=42
Answer:
B. No. The product of two fractions is the product of the numerators divided by the product of the denominators.
Step-by-step explanation:
For A: A is clearly false because you can multiply any fraction and it doesnt matter what the denominator is.
For B: The first part is correct, which is that to multiply two fractions, they dont have to have like/common denominators, the explanation part is also correct. When we multiply we multiply the numerator to the numerator and the denominator to the denominator.
For C: C is false because the first part says yes and we know that you can multiply any 2 fractions regardless of denominators.
For D: For D the first part is correct however, the explanation section is false you dont multiply the numerator to the denominator.
For E: You don't have to find the equivalent fraction to multiply because you can do that afterward.
I hope this helps, have a blessed day! :D
