Solve the equation for x by find the A , B , C of the quadratic then applying the quadratic formula
Volume of twin sized mattress =
39* 8.75* 75 = 25593.35 cubic inch
Volume of queen sized mattress =
60* 8.75* 80 = 42000 cubic inch
To fill 25593.35 cubic inch it takes 4 minutes
To fill 1 cubic inch it will take = 
minutes
So to fill 42000 cubic inch it will take = 
= 6.56 minutes.
Answer:
Cluster Sample
Step-by-step explanation:
Sometimes, a survey may involve people in a widespread geographical location. Taking samples from all part of the location may involve higher cost and even difficulty in accessing the whole area. Researchers therefore use a type of sampling method that help in overcoming this difficulty and still get results that can be used to judge the whole population.
This type of sampling is called cluster sampling. Cluster sampling involves sharing your population into clusters and randomly selecting two or more of the clusters. The researcher then samples from only the selected clusters.
In the question above, the population is already shared into clusters, in the form of neighbourhoods. The municipality then randomly selected 31 neighbourhoods out of the whole neighbourhoods in the city, just like in cluster sampling, then samples from only the selected neighbourhood. This is why the selected samples are cluster samples.
-18=x+10
move +10 to the other side
sign changes from +10 to -10
-18-10=x+10-10
-18-10=x
Answer: x=-28
