Question

13) The average age of 40 students is 8 years. If the age of
teacher is also included, then their average age increases by half a
year. What is the age of the teacher?
a. 45 years
b. 48.5 years
C. 28.5 years
d. 26.5 years​

Answer 1

Answer:

According to the question

Average age of 40 students of class is = 18 years

let the average age of 20 new students = x years

∴40×18+20×x=(18+12) years

720+20x60=372

720+20x30=37

720 + 20x = 1110

20x = 390

x = 19.5

∴ Average of newly admitted students is = 19 years 6 month

Answer 2

Answer:

28.5

Step-by-step explanation:

Average of 40 students = 8

average of 41 people after including teacher = 8.5

Age of 40 children = 8 x 40 = 320

Age of teacher and students together = 8.5 x 41 = 348.50

Age of teacher = 348.5 - 320 = 28.50years or 28years 6months