Question

the average age of boys in class is 15.5 years, while girls average age is 16.5 years. the average agevofvtotal students is 16 years. if there are 30 boys innclass then how many girls ?
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Answer 1

The no. of girls in the class is 30.

Step-by-step explanation:

Required formula:

• Average = [Sum of observation] / [No. of observation]

No. of boys in the class = 30  

The average age of 30 boys = 15.5 years

The average age of girls = 16.5 years

The average age of total students = 16 years

Let the no. of the girls in the class be denoted as “x”.

So, the total no. of students = x + 30

Based on the above-required formula, we can write the eq. as,

$\frac{(15.5*30) + (16.5 * x) }{30 + x} = 16$

⇒ [(15.5 × 30) + (16.5 × x)] = 16[30 + x]

⇒ 465 + 16.5x = 480 + 16x

⇒ 16.5x - 16x = 480 - 465

⇒ 0.5x = 15

⇒ x = 30 ← the no. of girls in the class

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Answer 2

ans:- ,the number of girls in classroom is 30 .