Out of total 10 students the average weight of 9 students is 69kg.If the weight of 10th student is 9kg more then the average of 10 student.so what is the average weight of students.
Answers
Answer:
total 9 students weight is 621
total 10 students weight is 621+9=630
average weight is 630/10=63
The average weight of students is 70kg.
We are required to find out the average weight of the 10 students.
Let it be x.
So, total weight of 10 students will be = ( 10 × x)kg = 10x kg.
Given that,
Average weight of 9 students = 69kg.
∴ Total weight of 9 students = (69 × 9)kg = 621 kg.
Weight of the 10th student = (Total weight of 10 students) - (Total weight of 9 students)
= (10x - 621) kg. ...(1)
In the question, it is mentioned that, weight of the 10th student is also equal to 9kg more than the average weight of 10 students (which is x).
So, we represent this statement as:
Weight of 10th student = (9 + x ) kg ...(2)
As (1) and (2), both are the same, representing the weight of 10th student, so we equate them as:
(10x - 621) = (9 + x )
⇒10x - x = 9 + 621
⇒ 9x = 630
⇒ x = 630/9 = 70
So, the average weight of the 10 students = x = 70kg.