Question

1. In a group of students, if a student aged 19 years is replaced by a student aged 25 years, the average age of the group increases by 0.4 years. Find the number of students in the grou

Answer 1

Answer:

Number of students in the group is 15.

Step-by-step explanation:

Let the total number of students in the group be "x" and the sum of ages of x students( including the 19 years old student ) be "a" years.

We know ( formula ),

Average = ( sum of quantities ) / ( number of quantities )

Therefore,

Average age of the students = a / x

According to the question : -

if a student aged 19 years is replaced by a student aged 25 years, the average age of the group increases by 0.4 years.

Now,

Sum of ages = ( a - 19 + 25 ) years

Mean = a / x + 0.4 years

Then,

= >  a / x + 0.4 = ( a + 25 - 19 ) / x

= >  ( a + 0.4 x ) / x = ( a + 6 ) / x

= >  a + 0.4x = a + 6

= >  0.4 x = 6

= >  4x = 60

= >  x = 60 / 4

= >  x = 15

Therefore, the number of students in the group is 15.

Answer 2

Answer:

hence ans is 15 number of students in group

(refer the attached image)