# Find how much younger is the new member

The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member?
This question is related to Accenture Interview

superstardlx Profile Answers by superstardlx Questions by superstardlx

• Member Since Aug-2008 | Aug 27th, 2008

let the members be a1,b,c,d,e,f,g,h,i,j .Let a2 be the younger member who replaces a1.
we have,
a1+b+c+......+j=a2+b+4+c+4+d+4+.....+j+4
=> a1+b+c+....+j=a2+b+c+..+j+36
hence,the oldest member is 36 years older than the new member

#### superstardlx Profile Answers by superstardlx

• Aug 27th, 2008

let the members be a1,b,c,d,e,f,g,h,i,j .Let a2 be the younger member who replaces a1.
we have,
a1+b+c+......+j=a2+b+4+c+4+d+4+.....+j+4
=> a1+b+c+....+j=a2+b+c+..+j+36
hence,the oldest member is 36 years older than the new member

#### rathinamraj Profile Answers by rathinamraj

• Jan 15th, 2009

Let 'O' be the old persons' age, and 'N' be the new persons' age and 9X be the age of rest of 9 persons.
then, (9X+N)/10=(9X+O-10*4)     (10*4=> coz 4 yrs back for 10 persons)
=> 9X+N=9X-40
=>N=-40 (which means the new person is 40 years younger than the old person).
and it solves the problem!!!

#### Harihar Profile Answers by Harihar

• Nov 27th, 2009

Let the old member be x
Remaining member be y
New member be z
Average ages be a

(x+9y)/10=a; --------------------(1)
4 years later
(9y +z+36)/10=a--------------(2)  //36 because collective ages of 9 person 4 years after
solving 1 and 2 you get

You get z+36=x
This means x is 36 year older then z

#### m_manic Profile Answers by m_manic Questions by m_manic

• Dec 14th, 2009

After four year increase in age is 36 years (one person is left). To get same average, the new member must be 36 years younger than the old member

#### muhammedkareem321 Profile Answers by muhammedkareem321

• Feb 1st, 2010

It is hard to say that it could be 36 or 40 since we dont have data. as per the give calucalation, we reach only one statement. i.e, the age difference is a1=(4+a2)

age of committe members= a1+b+c+d+e+f+g+h+i+j+(10*4)
age of committe members with new member=a2+b+c+d+e+f+g+h+i+j+(9*4)
i.e, => a1+b+c+d+e+f+g+h+i+j+(10*4)=a2+b+c+d+e+f+g+h+i+j+(9*4)
i.e, => a1+b+c+d+e+f+g+h+i+j+(40)=a2+b+c+d+e+f+g+h+i+j+(36)
i.e=> a1+40=a2+36
i.e=>a1-a2=40-36=4
i.e=> a1=4+a2

Therefore, we can conclude that the new member is 4yrs younger

#### jamesjac Profile Answers by jamesjac

• Feb 8th, 2010

Four years back, Let the sum of the Ages of the 9 members of the committee( Who still continues )  be M. Let the age of the 10th memeber at that time be R.  Hence the average age of the 10 members was  (  M + R) / 10.

Now the 10th member is  replaced with 11th member , whose current age is N.

The current average age of the committee is ( M +(9X4) +N )/10

Hence , (  M + R) / 10  =  ( M +36 +N )/10

Hence R = 36 +N.

Thus, the new member is 36 years younger to the old member.

#### ibulal Profile Answers by ibulal

• Jun 9th, 2010

On the inclusion of the new member in the committee, there is no change in the average age of the committee members as it was 4 years back implying:

The newly substitute in the committee is a younger candidate who reduces the average age to what it was 4 years back quantfying to 4*10 total decrease in the total age i.e. 40 years.

How ever since the new candidate replaces on of the older employee the resulting decrease will be only 36 years(9*4) and not for 10 persons...

Hence the younger member is 36 years younger.  