Answer:
Cluster sample
Step-by-step explanation:
This is an example of a cluster sample. In a cluster sample, the examiner divides the population into groups (each one of these groups is called a cluster) and once the examiner has these clusters, takes one of them and recollects the data from ALL the members of that cluster. In this case, the teacher divided the class in 3 different groups and then selects one of these groups and asks the average amount of time per week he/she spent studying.
The set of x ordinates or {1,2,3}
A farm had 480 acres more wheat than corn. Let use "W" to represent the Wheat and let use "C" to represent the corn. Hence, we have below:
W=C+480
The farmers collected 80% of the wheat and 25% of the corn and the area of the wheat is 300 acres less than the area of the corn:
W-0.8W=C-0.25C+300
0.2W=0.75C+300
We have two equations, two unknowns:
0.2(C+480)=0.75C+300
0.2C+96=0.75C+300
0.55C=294
C=534.55
