Answer:

Step-by-step explanation:
Donna's Rate is 
Rico's Rate is 

Cross-Multiply



Donna's Rate is 
Rico's Rate is 

there will be 12 groups of 7
and 1 group of 6
Answer:
5 * 10^10
Step-by-step explanation:
(9 * 10^10) - (4 * 10^10)
If the * 10^x are both the same then just take the numbers away.
Based on the information given, it can be noted that the problem with the research is the problem of validity.
<h3>
Problems with validity.</h3>
It should be noted that in a research, a problem with validity takes place when there's a lack of reliability of the independent variable.
Also, it is a result of lack of representativeness of the independent variable and a lack of impact of the independent variable.
In this case, the researcher sets out to measure drug use on US college campuses by asking a representative sample of undergraduates whether they are currently receiving federal grants or loans. It should be noted that the question asked doesn't relate to the research.
In conclusion, there's a problem with validity.
Learn more about researches on:
brainly.com/question/25257437