Question

The average age of a board of 10 advisors of a company is the same as it was 3 years ago, on account of the replacement of one of the older advisors by a younger man. How much younger is the new man than the director whom he replaced?​

Answer 1

Answer:

40

Step-by-step explanation:

Let the members be Old Having age O + other 9 having ages x and New one having age Y

Sum of their ages = (Y + 9 × x) and average = (Y + 9 × x)/10

Before 4 years sum was (O + 9 x – 10 × 4) and average = (O + 9 x – 10 × 4) /10

equating, Y + 9 x = O + 9x – 40

Y = O – 40

Younger is 40 years younger than Old one answer : 40 years

try it in funny way :)

let all 10 member age is 5, 5 years

so avrg of member in current = (5+5+5+5+5+5+5+5+5+5)/10 = 50/10

before 4 years memners avrg age was = (1+1+1+1+1+1+1+1+1+1)/10= 10/10

bt sum of age should be same as 50 as said in d qstn it means any of members age should be 41 years

so sum of age will be 50 years

so replaced member age should be of 41 years

then how much younger is d new member = 41-1= 40

:)

Answer 2

Answer:

30

Step-by-step explanation:

Let's assume the sum of age of unchanged members 3 years ago be x.

Age of replaced member be y and age of new one be z.

Average age of board is same as the previous one,

(x+y)/10 = (x+z+30)/10

30 accounts for the time lapse of 3 years for each 10 members.

» y-z = 30

Age gap is 30 years.