Question

There are 50 boys in a class whose average age is 12 years. There are 40 boys in another class whose average age is 15 years. what is the average age of both the classes taken together​

Answer 1

$\huge\mathfrak\orange{\underline{Answer:18.34\:years}}$

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$\textbf{\underline{\underline{Step-By-Step\:Explanation:}}}$

In this question, Average age of students of 2 classes are given. In the first class, there are total 50 boys while in the other class, there are total 40 boys. From this, It is clear that,

→ Total students => 50 + 40 = 90 students

Now,

In the first class,

Total students = 50

Average age = 12 years.

$\sf\therefore {Average\:Age}=\dfrac{Total\:ages}{Total\:Students}$

So,

$\sf {Total\:Ages}={Total\:students}\times{Average\:Age}$

Substitute the given values in the formula.

we get,

$\sf =50\times{21}\\\\ = 1050$

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In the second class,

→ Total students = 40

→ Average age = 15 years.

Now,

Substitute the value in the above formula to get total ages.

$\sf =40\times{15}\\\\ ={600}$

Finally,

Total ages of both the classes :

= 1050 + 600

= 1650

Total students of the classes :

= 50 + 40

= 90

Now, Average age of the both the classes together

$\sf=\dfrac{1650}{90}$

$\sf=18.33333...\\\\ =18.34\:(Approx.)$

Hence,

The average age of the both the classes is 18.34 years.

$\rule{200}2$