Question

The average weight of the class of 35 students was 45 KG. with the admission of a new student the average weight came down to 44.5 kg. find the weight of a new student

Answer 1

The weight of the new student is 27 kg.

Average weight

= total weight ÷total number of students

1) Define variables

Let the total weight of the 35 students be y kg and the weight of the new student be x kg.

2) Find the total weight of the 35 students

$45 = \frac{y}{35}$

y= 35(45)

y= 1575 kg

3) Write an expression for average weight of students after the addition of the new student

New total number of students

= 35 +1

= 36

Total weight

= total weight of 35 students +weight of new students

= y +x

$44.5 = \frac{y + x}{36}$

4) Substitute the value of y

$44.5 = \frac{1575 + x}{36}$

5) Solve for x

36(44.5)= 1575 +x

1602= x +1575

Subtract 1575 from both sides:

x= 1602 -1575

x= 27

Thus, the weight of the new student is 27 kg.