Mrs. Hopkins divides her 120 seventh-grade students into three groups. If the second group is 1.5 times larger than the first group, and the third group is 2.5 times larger than the first group, how many students are in each group?



Answer :

Sure, I will explain the solution step-by-step.

1. Understanding the Problem:
Mrs. Hopkins has 120 seventh-grade students that she needs to divide into three groups. There are specific conditions given:
- The second group has 1.5 times the number of students as the first group.
- The third group has 2.5 times the number of students as the first group.

2. Define Variables:
- Let [tex]\( x \)[/tex] be the number of students in the first group.

3. Express the Other Groups in Terms of [tex]\( x \)[/tex]:
- The second group has [tex]\( 1.5 \times x \)[/tex] students.
- The third group has [tex]\( 2.5 \times x \)[/tex] students.

4. Set Up the Equation:
Since the total number of students is 120, we can set up the following equation:
[tex]\[ x + 1.5x + 2.5x = 120 \][/tex]

5. Combine Like Terms:
Combine all terms involving [tex]\( x \)[/tex]:
[tex]\[ (1 + 1.5 + 2.5)x = 120 \][/tex]
Simplifying inside the parentheses gives:
[tex]\[ 5x = 120 \][/tex]

6. Solve for [tex]\( x \)[/tex]:
To find [tex]\( x \)[/tex], divide both sides by 5:
[tex]\[ x = \frac{120}{5} = 24 \][/tex]

7. Determine the Number of Students in Each Group:
- First group: [tex]\( x = 24 \)[/tex] students
- Second group: [tex]\( 1.5 \times x = 1.5 \times 24 = 36 \)[/tex] students
- Third group: [tex]\( 2.5 \times x = 2.5 \times 24 = 60 \)[/tex] students

Therefore, the number of students in each group is:
- First Group: 24 students
- Second Group: 36 students
- Third Group: 60 students