Answer:
The value of x is -20/3.
Step-by-step explanation:
If a ratio of skiers and snumboarders is 1:2, and if there are 1250 snowboarders more than skiers, it means that is that there 2500 snowboarders and 1250 skiers.
How to check it? 2500 is 1250 more than 1250 and the ratio is still 1:2 (there are two times more snowboarders than skiers). Both conditions are fulfiled, so it's correct.
So if you distribute 4 in the first parentheses, you get 12x+20y+8z.
Then you distribute 3 in the second parentheses. You'll get 3x-3z. That all equals 12x+20y+8z+3x-3z.
Now you have to start combining numbers with the same variable. Start with x. 12x+3x is 15x.
y has no other common variable, it's left alone.
8z-3z is 5z
All together now with the numbers in simpler form, the equation is 15x+20y+5z
Jenna's would be the right answer because when you distribute 5 in her answer you get 15x+20y+5z
Answer:
a) Observational study
b) No
c) No
-Eating habits
-Age
-Health hystory
Step-by-step explanation:
Hello!
An observational study is one where the investigator has no control or intervenes on it. He just defines the variable of interest and merely collects and documents the information. These types of studies are usually made as precursors to a more formal experimental study, to have an idea of what's to be expected from the population.
In this example, the researcher merely took the information of interest from the survey that was taken. The researcher did not intervene in any way in the experiment. Because of the lack of intervention from the researcher, it is not valid to use the conclusions of this experiment to generalize to all American adults. For instance, it is not sure that the sample is representative, all people responding to the survey may be healthy or have certain eating habits. This also shows that many confusing factors are not taken into account like:
-eating habits (from eating healthy to extreme cases like being vegetarian/vegan or eating only fast food)
-age, the age range is not defined, if the sample is taken from surveys answered by people in their early 20s it will be different in both eating habits and health information as if the interviewees are in their 30s or 40s
-before health issues, there can be other health conditions that may be affecting the interviewees.
I hope it helps!
A reflection over the x-axis
