Aptitude - Problems on Ages - Discussion

Since given 5 children=50
let one children be x
given interval 3 each
so x+(x+3)+(x+6)+(x+9)+(x+12)=50
5x+30=50
x=20/5
x=4..

Younger means the person who born at last, then who is the last one, according to problem the person x+12. Submit X value in x+12=16.

Can you please any one clear my doubt ?

@kumuda sub x value in all then u will get 4,7,10,13,16.

So among them d least age is 4 i.e younger one.

Let x+(x-3)+(x-6)+(x-9)+(x-12)=50
5x-30=50
5x=80
x=16
is this correct or not?
if it is wrong then explain the reason..

For all who don't understand here is the simple explanation.

Let the last child ( 5th ) born be x years old,
3 years before the 4th child was born so his age has to be x+3,
now the 3rd child was born 3 years before the 4th child. so the age of 3rd child is 3+3 ie 6+x.
so on..we get
x ( last child ) + x+3 ( a child before x )+ x+6 + x+9 + x+12 =50.

so x+x+x+x+x + 3+6+9+12 =50
5x + 30 =50
5x = 50-30
5x = 20
x = 4.
where x is the youngest child.

Explanation in Hindi: :P
jo last baccha hua uski age x hai...jo usse 3 saal pehle paida hua hoga toh uski age to x se 3 saal badi ho hogi na...so x+3,
so usse 3 saal pehle hua hoga uski age x se 6 saal badi and so on.

Lets assume that the first elder son age is X, then the difference in the age of 3 years among the consecutive child summing to the total age of 50 would be follow.Here (X-3) corresponds to 2nd elder child age and (X-6) corresponds to 3rd elder child age and so on

x+(x-3)+(x-6)+(x-9)+(x-12)=50 ----> (1)
5x-30=50
5x=80
x=16

The (x-12) in equation 1 corresponds to 5th child age and by substituting X = 16 & (X-12) = Y in equation 1 we ill get 5th child age as below

16 + 13 + 10 + 7 + Y = 50
46 + y =50
Y = 50-46
Y = 4

I have a other way to solve it.
Avg of 50 = 50/5 = 10.
Hence, the middle No. In the series i.e. x+6=10 (middle no is the avg value of the series).
So x = 10-6= 4.

I have an other way to solve it.

When 1st baby came and he became 3years old than other baby came. When 2nd baby became 3years old than 3rd baby came and 1st baby became 6years old like it 3x4 = 12, so 1st baby became 12 years old than 5th baby came 1st baby became 15 years old.

Like, 1st 15 2nd 12 3rd 9 4th 6 5th 3,

3+6+9+12+15=45 thair is 5 years. So give one year.

It will be.

4+7+10+13+16=50.

The Problem can be solved using Arithmetic Progression:

S = n/2{2a+(n-1)d}

a = youngest age(We have to calculate this)
n = Total no. of people(5)
d = Difference of Ages in the progression(3)
S = Summation of their ages(50)

X+12+x+9+x+6+x+3+x=50.

5x+30=50.

(x+6) =10.

X=4.