Question

out of 8 student the average age of the
first 5 is 12 years and last & is to
find the average age of 8 students​

Answer 1

Step-by-step explanation:

The average age of 20 students is 12 years.

∴ Total age of 20 students =20×12=240years

It is given that, student who is 10years old left the class.

∴ Total age of 19 students =240−10=230years

An then 2 new students entered and average remain same.

∴ Total age of 21 students =21×12=252years

⇒ Total age of 2 new students who entered in the class =252−230=22years

Let x and y be the two new students.

∴ x+y=22 ------ ( 1 )

According to the question,

x−y=4 ----- ( 2 )

Now adding (1) and (2), we get,

x=13

Putting value of x in equation ( 1 ) we get,

y=9

∴ The age of younger one is 9years.