Answer:
syd is 23 and dev is 69
Step-by-step explanation:
Let Dev's age be x and Syd's age be y
Since Dev is 3 times older than Syd, we may write
x
=
3
y
Since the sum of their ages is 92, we may write
x
+
y
=
92
Now replacing x with 3y, we get :
3
y
+
y
=
92
Hence
y
=
92
4
=
23
and so Syd is 23 year old.
Back substituting we get Dev is 69 years old.
Answer:
30 degrees
Step-by-step explanation:
u dot v=1*4+1*4+1*4+0*4=4+4+4+0=12
|u|=sqrt(1^2+1^2+1^2+0^2)=sqrt(3)
|v|=sqrt(4^2+4^2+4^2+4^2)=sqrt(4*4^2)=2*4=8
cos(theta)=u dot v/(|u||v|)
cos(theta)=12/(sqrt(3)*8)
cos(theta)=3/(sqrt(3)*2)
cos(theta)=sqrt(3)/2
theta=30 degrees
Answer:
180 - 46 - 83 = 51 is the measure of angle C
the exterior angle at angle C, and angle C, are supplementary. since angle C is 51 because of the interior angle triangle sum theorem, then the exterior angle is: 180 -51 = 129 degrees.
Step-by-step explanation:
I hope this helps :)
Answer:
The 95% confidence interval estimate for the true proportion of adults residents of this city who have cell phones is (0.81, 0.874).
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 
.
For this problem, we have that:
95% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
The lower limit of this interval is:
The upper limit of this interval is:
The 95% confidence interval estimate for the true proportion of adults residents of this city who have cell phones is (0.81, 0.874).
B is the y-intercept. in this example, b=50
