There are 45 students in a class, 20 of whom have 2 siblings, 15 of whom have 1 sibling, while the rest have no siblings.
How many siblings do the students in the class have on average?
To solve this problem, we'll follow these steps:
- Step 1: Determine the number of students with no siblings.
- Step 2: Calculate the total number of siblings.
- Step 3: Use the weighted average formula to find the average number of siblings per student.
Step 1: Determine the number of students with no siblings.
The problem provides us with the following information:
- 20 students have 2 siblings.
- 15 students have 1 sibling.
- Total number of students = 45.
The number of students with no siblings can be calculated as:
Number of students with no siblings = Total number of students - Students with 2 siblings - Students with 1 sibling.
45−20−15=10
Step 2: Calculate the total number of siblings.
The total number of siblings is calculated by summing the product of the number of siblings and the number of students in each category:
Total number of siblings = (2 siblings × 20 students) + (1 sibling × 15 students) + (0 siblings × 10 students)
(2×20)+(1×15)+(0×10)=40+15+0=55
Step 3: Use the weighted average formula.
The weighted average for the number of siblings per student is given by:
Average number of siblings = Total number of studentsTotal number of siblings
4555=911≈1.22
Therefore, the students in the class have, on average, 1.22 siblings.