Aptitude - Problems on Ages - Discussion

How come 4, here?

Well said @Pradnyaa.

Good explanation @Pallavi.

Here, first, understand the question.

6year ago, the ratio of the ages of Kunal and Sagar was 6 : 5. --> it means that ration of both is given for 6years ago.

So that, the present age is 6x+6 and 5x+6.

Let, Kunal present age = x.
& Sagar present age = y.

STEP1
6yr ago
(x-6)/(y-6)=6/5
5x-6y=-6 .----> eq(1)

STEP2:

4yr hence;

(x+4)/(y+4)=11/10.
10x-11y=4 ---->eq(2).

Solving eq. Simultaneously.
x=18 & y = 16.
Hence Sagar age is 16yr old.

My answer will be simple and easy.chexh this out:

6 years ago the ratio is 6x/5x(since a/b so we should take it as ax/bx).
Now the present ages are 6x+6/5x+6(since 6x/5x are the ages 6 years before),
After four years to the present age so (6x+6)+4/(5x+6)+4 = 11/10,
60x+100 = 55x+110,
5x = 10,
X = 2.

Since the present age of the second guy is 5x+6.
5(2)+6.
=16(final answer).

6:5 cross multiple both ratios.

11:10(difference)= 1 * 10 (time between ratios)
55 ~60 = 5
So if 5= 10.
1=5.

Now multiple with the past age ration you will get;
K = 12 , S=10.

And for Sagar's present age add 6yrs you will get 16 years.

No need to crack ur head just read the question, write the equation and solve it (question speaks itself):

Ist condition:-

k-6/s-6 = 6/5 ..................I

IInd condition:-

k+4/s+4 = 11/10 ...................II

So from I & II we got:-

k = 18
And s= 16 (required answer...)

Let Kunal age be 'x' and Sagar age be 'y'.

6 years ago,
Kunal age is (x-6) years and Sagar age is (y-6) years and their ratio will be 6/5 (given).

x-6/y-6 =6/5 --eq 1.

According to second statement,

x+4/y+4 = 11/10 --eq 2.

Solving these two equations:

5x-30=6y-36 (eq3) and 10x+40=11y+44 (eq 4).

Solving eq 3 and 4 as.

10x+40=11y+44.
-2 (5x-30=6y-36).

------------------------.

10x+40=11y+44.
-10x+60=-12y+72.

------------------------.

100= -y+116.
y= 16 years.

Best solution, Thanks @Amrita.