The average of 30 boys of a class is equal to 15 yrs. When the age of the class teacher is included the average becomes 16 yrs. Find the age of the class teacher.46 yrs
Answers
ANSWER
ANSWER
Given :------
Average of 30 boys of class = 15 years .
After teacher age included new average = 16 years .
We have to Find age of Teacher ....
Formula :------
Average is the Mean , Middle value of the number , it is Found by, when we divide all numbers sum by their number ...
Average = sum of observation / Total Number of observation ..
________________________________
it is given that average of 30 boys of class is 15 years.
Putting value in formula we get,
→ 15 = sum of age of all boys /30
(Cross - multiply) we get,
→ sum of age of all boys = 15 × 30 = 450 years..
_________________________________
Now,
when Age of teacher also included , than Average becomes 16 years .
→ Total members now = (30 students + 1 teacher) = 31
Again,
→ 16 = sum of all members / 31
→ sum of all members = 16×31 = 496 years ..
_________________________________
Now,
This is the age of 30 students + 1 teacher ,
and , we already have 30 students total age = 450 years.
Hence, Teacher age = 496 - 450 = 46 years ...
So, Age of Teacher was 46 years..
__________________________________
★ Shortcut ★
→ [[[[ Teacher age = ☛ Increased Average = 1 year
☛ Number of students = 30 .
Putting values we get,
➠ Teacher Age = 16 + 1 × 30 = 46 years ..
Hence, Teacher was 46 years old ...
___________________________________
#BAL
PLEASE MARK AS BRAINLIEST ANSWER
Step-by-step explanation:
let sum of 30 boys age is equals to x
x÷30 = 15 -------- (i)
x+y ÷ 31 = 16 ---------(ii)
x = 450
450+y = 16 × 31
450+y = 496
y = 496-450
= 46
teacher age is 46 yrs