The average weight of a group of 15 students is 32.5 & the average weight of another group of 17 students is 28.5. Find the average weight of both groups together.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 30.375.
Average = sum of the weight of students/total number of students
The average weight of 15 students = 32.5
The average weight of 17 students = 28.5
The sum of the weight of 15 students = (15 × 32.5) = 487.5
The sum of the weight of 17 students = (17 × 28.5) = 484.5
The total number of student in both the group = (15 + 17) = 32
The sum of the weight of 32 students = (487.5 + 484.5) = 972
The average weight of 32 students = 972/32 = 30.375