Question

Average age of students in a class of 18 students is
16 year and 3 month when 4 students left the class
new average age of class becomes 15 years and 3
months. Find the average age of students who left
the class.​

Answer 1

Answer:

answer is 15 year 6 month

Answer 2

Answer:

Average age of 4 students is 19.75 years

Step-by-step explanation:

In the question,

Average age of 18 students = 16 year 3 month = $16+\frac{1}{4}=\frac{65}{4}\ years$

Also,

After 4 students left,

Average age of 14 students = 15 years 3 months = $15+\frac{1}{4}=\frac{61}{4}\ years$

Now,

$Average=\frac{Total\ sum\ of\ age}{Number\ of\ students}\\ \frac{65}{4}=\frac{(14\times \frac{61}{4})+Sum\ of\ age\ of\ 4\ students}{18}\\ 292.5=213.5+Sum\ of\ age\ of\ 4\ students\\Sum\ of\ age\ of\ 4\ students=79$

Therefore, the Total age of the 4 students who left is = 79

So,

The average age of them is given by,

$\frac{79}{4} =19.75$

Therefore, the required average age of 4 students is 19.75 years.