Question

The average weight of 42 students of a class was 52.5 kg. After 8 new students
joined the class, its average weight increased by 1.44 kg. What is the average
weight of 8 new students who joined the class ? (in kg)
1) 57.5
2) 60.5
3). 59
4) 63
5) 61.5​

Answer 1

5) The average weight of 8 new students is 61.5 kg.

Step-by-step explanation:

As given in question that the average weight of 42 students was 52.5 kg.

After 8 new students joined the class, its average weight increased 1.44 kg.

So, the average weight of 50 students = 52.5 + 1.44

                                                                  = 53.94 kg

We have to find the average weight of 8 new students.

Let the average weight of 8 new students is x.

We know that,

$Average = \frac{total\ weight\ of\ 42\ students\ +\ total\ weight\ of\ 8\ students }{total\ number\ of\ students}$

$53.94 = \frac{42\times52.5\ +\ 8\times x}{50}$

53.94 x 50 = 2205 + 8x

2697 - 2205 = 8x

492 = 8x

$\frac{492}{8} = x$

∴ x = 61.5

Therefore, the average weight of 8 new students is 61.5 kg.