Question

In a random sample of 30 sixth graders, 9 has traveled outside of the united states. there are a total of 120 sixth graders in the school. predict how many students have traveled outside of the united states.

Answer 1

The first thing we must do is find the percentage that has traveled outside of the United States.
 For this, we make the following rule of three:
 30 ---------> 100%
 9 -----------> x
 We clear the value of x:
 x = (9/30) * (100)
 x = 30%
 Then, for 120 sixth graders in the school we have:
 (0.30) * (120) = 36
 Answer:
 36 students have traveled outside of the united states