Question

The average weight of students in a class of 35 students is 40 kg. If the weight of the teacher be included, the average rises by $\frac{1}{2}$ kg, the weight of the teacher is

• A. 40.5 kg
• B. 50 kg
• C. 41 kg
• D. 58 kg

Answer 1

The correct option is D 58 kg

Let the weight of the teacher is w kg, then
$40+\frac{1}{2}=\frac{35\times 40+w}{35+1}$
$\Rightarrow 36\times 40+36\times \frac{1}{2}=35\times 40+w\Rightarrow w=58$
$\therefore Weightoftheteacher=58kg.$