Even # --------- if it ends with 0, # of ways = 6*5*4 = 120 if not, 3 ways for ending digit, 5 ways for 1st digit, 5*4 for middle digits = 300
so total ways = 420
odd # --------- 4 ways of ending digit, 5 ways for 1st digit, 5*4 for middle digits = 400 ways
< 4000: ---------- 3 ways for starting digit, 6*5*4 ways for remaining digits = 360 ways
> 3000 & < 4000 ------------------------ 1 way for starting digit , 6*5*4 for remaining digits = 120 ways
Answer:
1- a
2- b
3- c
4- d
Step-by-step explanation:
For any operation you have to separate the numbers from the unknown quantities (x, y) and then simplify them by solving them with quantities you are familiar with.
Example:
7x + 8 - 6 + 3x
7x + 3x + 8 - 6
you can only solve operations if they are both natural or algebraic numbers
10x + 2
Hope it was helpful ;)
Answer:
The main difference between an observational study and an experiment is the inclusion of a random sample.
Step-by-step explanation:
In an observational study, the researchers do not interfere with the method the data is collected. In an investigation of how regularly the studying improves marks, the researchers sample people from the population who has studied regularly and those who haven't and then collect the average marks obtained by each of the groups. We can only accomplish an association among the response variable and the explanatory variables because there may be some other variable that may affect both the explanatory and the response variable, thus making it look as if there is a relationship among them.
But in an Experiment, the researchers actually interfere with the method the data is collected. In an experiment, each case is randomly assigned to the treatment groups, i.e. to say that each of the cases has an equal chance of being in both groups. These kinds of studies help us to establish causal connections between the response variable and the explanatory variables because random assignment makes sure that they are equally spread among both the groups.
So, the primary difference between an observational study and an experiment is that in case of an observational study there is no random assignment but in case of an experiment there is a random assignment.
We know that for √x to be meaningful, we must have x ≥ 0.
If we square both sides of the inequality, we have
x < 4²
x < 16
Thus the whole solution is
0 ≤ x < 16
The following choices are valid solutions to the inequality:
B. 12
C. 2
E. 5
