Question

The average weight of a class of 24 students is 35 kg. If the weight of the teacher would be included, the overage sizes by 400g. What is the weight of the teacher?
A. 40 Kg
B. 44 Kg
C. 41 Kg
D. 45 Kg

Answer 1

Hint: Average weight is the total sum of weight divided by the total number. To find the total weight sum, we can multiply average into total no.

Complete step-by-step answer:
To get the sum of the weight of a student, we are given with the average and the no. of students. On the other hand, we are given an average of students and teachers. If we get to know the total student’s weight sum and students plus teacher weight sum, we can subtract and easily take the teacher's weight.
400g=0.4kg
As given information says that the average of 24 students is 35 Kg. Then total weight sum will be equal to $35 \times 24 = 840\,{\text{Kg}}{\text{.}}$
When we include the weight of the teacher, the total member becomes 25 and average sizes to 35.4 Kg.
Hence, here the total weight will be $35.4 \times 25 = 885\,{\text{Kg}}.$
Hence, the difference will be the weight of the teacher, which is
$885 - 840 = 45\,{\text{Kg}}{\text{.}}$
Option D is the correct answer.

Note: The average of a mean is total sum upon total number. Every precision value matters in this type of question.