To answer the question, first we need to calculate the percentage of students in the marching band who play the trumpet. Here's how to do it:
1. Begin by noting down the total number of students in the band. In this case, there are 150 students.
2. Secondly, write down the number of students who play the trumpet. Here, 30 students play the trumpet.
3. The next step involves calculating the percent of students who play the trumpet. The word "percent" comes from "per centum", which means per hundred. So, to find the percentage of the students who play the trumpet, we divide the number of trumpet-playing students by the total students, then multiply the result by 100.
Using this formula, let's calculate the percentage:
- Divide 30 (trumpet players) by 150 (total students). This gives you a decimal, 0.2.
- Hence, multiplying 0.2 by 100 converts it to a percentage.
Doing these operations, the percentage of students in the marching band who play the trumpet is 20%.
So, to answer the main question, you are looking for a number line marked with percentages (from 0 to 100) and you should mark the number line at 20% since that matches the calculated percent of students who play the trumpet.