Answer:
a) cluster sampling
Step-by-step explanation:
In cluster sampling method, each member of a population is assigned to one and only one group.This means clusters are formed through probability method usually a simple random sampling.The participants in the clusters are the only one to be surveyed.
In this example, simple random sampling is used to identify 12 home rooms(cluster) where a group of 20 students (participants) in each room is given the survey.
Answer:

Step-by-step explanation:
Put <em>n = 10</em> to the equation 

Be:
Number of hours: n
<span>The cost of renting a bike for the first hour is $7:
n=1→f(n)=f(1)=$7
</span>He is charged $2.50 for every additional hour of renting the bike:
f(n)=f(n-1)+2.50, for <span>n ≥ 2
</span>
f(1)=7; f(n)=f(n-1)+2.50, for <span>n ≥ 2 (sixth option)
</span>
f(n)=f(1)+2.50(n-1)
f(n)=7+2.50(n-1)
f(n)=7+2.50n-2.50
f(n)=2.50n+4.50 (fifth option)
Answers:
Fifth option: f(n)=2.50n+4.50, and
Sixth option: f(1)=7; f(n)=f(n-1)+2.50, for <span>n ≥ 2</span>
Answer:
(-3,5) Quad 2
(4,-1) Quad 4
(2,0) Positive X axis
(2,2) Quad 1
(-3,-6) Quad 3
Step-by-step explanation: