There are 27 schools participating in the regional band competition. Every school brought 38 band members. Find the best way to estimate total band members are in the competition?

The correct answer is: 25 × 40

Here we need to find out the best way to estimate the total band member in the competition.
Firstly, We have 27 total school .
And Each school having total 38 band member.
So the total member are
1 school= 38
27 school = 27 x 38
We need take the best best estimation for these number
Lets take estimate value for school= 25, which is nearest and round value
And , lets take the estimate value for the Band member = 40 , which is nearest and round value.
Now , find the total number of band member:
1 school= 40 members
25school= (40 x 25)member
Therefore, 25 × 40 the correct estimation(option (c)) .

Nearest and round value is more accurate for your solution. You can apply This methods in many similar question. And also estimate value is not accurate value or exact solution of your question but it gives you the idea about exact solution.