Question

The mean age of 3 students was calculated to be 17 years when a fourth student's age was added, the mean age reduced to 16years.how old is he the fourth srudent.

Answer 1

Answer:-

13 years

Explanation :-

Let the total age of three students be x

we know that,

mean = total sum / total no. of obs

ATQ,

mean of 3 students => 17 years

x/3 =17

=> x = 51

•°• total age = 51

ATQ,

fourth student is added to reduce mean age to 16 years

let, the age of 4th student be y

•°• (51+y)/4= 16

=>51+y = 64

=>y= 64-51

=>y= 13

Hence, the age of 4th student is 13 years.

Answer 2

Answer:

Let the age of 3students be x

Mean=Total sum/total no of abs

ATQ,

mean of 3students=>17years

x/3=17

x=51

Total age=51

4th student is added to reduce mean age to 16years

let the age of 4th student be y

(51+y)/4=16

51+y=64

y=64-51

y=13

so the age of 4th student is 13 years