Question

The average age of 40 students of a class is 15 years. An 18 year-old student left the class and a new student was admitted. As a result the average age fell to 14.885 years. Find the age of the new student.

Answer 1

Answer:

Answer:age of new student is 13.4 years

Step-by-step explanation:

SUM of ages all 40 students =average age times 40

=15*40=600

after leaving 18 years old student

SUM of ages of 39 students will be 600-18=582

after adding new student with age x

SUM of ages of 40 students will become 582+x

and the average would be (582+x)/40

which is given as 14.885

so we get equation

(582+x)/40=14.885

582+x=14.885*40=595.4

x=595.4-582

x= 13.4

age of new student is 13.4 years

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Answer 2

the sudent age is 13.4

Step-by-step explanation:

SUM of ages all 40 students =average age times 40

=15*40=600

after leaving 18 years old student

SUM of ages of 39 students will be 600-18=582

after adding new student with age x

SUM of ages of 40 students will become 582+x

and the average would be (582+x)/40

which is given as 14.885

so we get equation

(582+x)/40=14.885

582+x=14.885*40=595.4

x=595.4-582

x= 13.4

age of new student is 13.4 years