Question

The average age of 5 students is 9 years . out of them the ages of 4 students are 5,7,8 and 15 years .what is the age of the remaining students.​

Answer 1

Answer:

10 years

Step-by-step explanation:

Let the age of the remaining student be x years.

$Average \:of\:ages = \frac{Sum \: of \: ages }{No. \: of \: students} \\ \\ 9 = \frac{5 + 7 + 8 + 15 + x}{5} \\ \\ 9 = \frac{35+ x}{5} \\ \\ 9 \times 5 = 35 + x \\ \\ 45 = 35 + x \\ \\ 45 - 35 = x \\ \\ x = 10 \: years$

Answer 2

Answer:

The age of the remaining student = 10 years

Step-by-step explanation:

Let the age of the remaining student = x

Average age of 5 students  = 9 year

Sum of the age of 5 students  = 9*5 = 45 years

5 + 7 + 8 + 15 + x = 45

               35 + x = 45

                        x = 45 - 35

                        x = 10

The age of the remaining student =  10 years