Answer:
Part a
For the given study, the explanatory variable or independent variable is given as regularity or frequency of exercise. This variable is classify as categorical variable because variable is divided into two categories such as whether participant exercise 5 or more days a week or not.
Part b
For the given study, the response variable or dependent variable is given as frequency of colds. This variable is classified as quantitative variable because we measure the quantities or frequency of number of colds.
Part c
A confounding variable for this research study is given as incidence of upper respiratory tract infections that provides an alternative explanation for the lower frequency of colds among those who exercised 5 or more days per week, compared to those who were largely sedentary. This confounding variable is categorical in nature.
Answer:
The amount of the chemical flows into the tank during the firs 20 minutes is 4200 liters.
Step-by-step explanation:
Consider the provided information.
A chemical flows into a storage tank at a rate of (180+3t) liters per minute,
Let
is the amount of chemical in the take at <em>t </em>time.
Now find the rate of change of chemical flow during the first 20 minutes.

![\int\limits^{20}_{0} {c'(t)} \, dt =\left[180t+\dfrac{3}{2}t^2\right]^{20}_0](https://tex.z-dn.net/?f=%5Cint%5Climits%5E%7B20%7D_%7B0%7D%20%7Bc%27%28t%29%7D%20%5C%2C%20dt%20%3D%5Cleft%5B180t%2B%5Cdfrac%7B3%7D%7B2%7Dt%5E2%5Cright%5D%5E%7B20%7D_0)


So, the amount of the chemical flows into the tank during the firs 20 minutes is 4200 liters.
Answer:
3.14
Step-by-step explanation:
Answer:
x=11
Step-by-step explanation:
You do 38/3x+3 and 19/x+7 and then cross mulitply and get 57x+57=38x+266. Then yoy subtract 57 from 266 and get 57x=38x+209. Now you have to subtract 38 from 57 and then answer will be 19. So now you have 19x=209. Finally you divide 209 by 19 and get x=11. Good luck!