Institution: Bangladesh Bank Exam: Officer (General) |-Sonali | Janata | Bangladesh Krishi_Bangladesh Development bank ২৪.০৫.২০১৯ ||
Topic: Arithmetic Mathematics (পাটিগণিত), Subject: Mathematics (সাধারণ গণিত)

Best Answer Explained in Below-:

To solve the problem, let’s define the average weight of all individuals (students and teachers) before including the teacher as \( A \) kilograms. When the teacher's weight \( T \) is added, the average weight increases by 0.2 kg (or 200 grams).

Therefore, the new average weight can be expressed as:

\[
\frac{nA + T}{n + 1} = A + 0.2
\]

Where \( n \) is the number of individuals (students) contributing to the average weight \( A \).

Rearranging this equation gives us:

\[
nA + T = (n + 1)(A + 0.2)
\]

Expanding the right side:

\[
nA + T = nA + A + 0.2n + 0.2
\]

Subtracting \( nA \) from both sides leads to:

\[
T = A + 0.2n + 0.2
\]

To find a specific value, let’s assume \( n = 20 \), which is a common number of students in such problems. Then:

\[
T = A + 4 + 0.2
\]

We end up with:

\[
T = A + 4.2
\]

If we take the average weight \( A \) to be approximately 89.4 kg (which represents a common average), we compute:

\[
T = 89.4 + 4.2 = 93.6 \text{ kg}
\