Aptitude - Problems on Ages - Discussion

Lovely please read question carefully..........

"At present age of father is (3)times more than his son"
(X=3)
"after 8 years age of father is (2 1/2)times more than his son"
(X= 2 1/2)
"AFTER 8 YEARS WHAT IS THE SONS AGE (i.e here, age of the son will be reducing half,gap of 8 years)"
So(X=2)
[1years->3times
8years->2 1/2times
16years->2times
24years->1 1/2times
32years->1times......................]

Step 1: Father is aged three times more than his son Ronit.
Let's assume Son's Age as X,
Father's Age = X+3X = 4X.

Step 2. After 8 years, he would be two and a half times of Ronit's age.
4X+8 = 2.5(X+8),
4X+8 = 2.5X+20,
4X-2.5X = 20-8,
1.5X = 12.
X = 12/1.5.
X = 8.

So, Son's Age (X) = 8 and Father's Age 4X = 4(8) = 32 [We found the actual Age].

Now add 8 years: Son's Age = X+8 =8+8 =16 and Father's Age = 4X+8 =32+8 =40.

After a further 8 years, how many times would he be of Ronit's age?
Now add 8 years: Son's Age = 16+8 = 24 and Father's Age = 40+8 = 48.

So Correct answer is 2 times.

Let Rohit present age = x.
Father's present age=x+3x=4x.

(Because they mentioned he is 3 times more than Rohit's age not 3 times Rohith age so it's not 3x but its x+3x=4x).

After 8 yrs means Rohith age=x+3.
Father age=4x+3.

Father age is 2 1/2 times means( 2*2+1)/2=5/2 times,
so 4x+8=5/2*(x+8),
8x+16=5x+40,
3x=24,
x=8.
After another 8 yrs.
Father age/rohith age=(4x+16) / (x+16)
Fa / ra=(48/24) [since x=8].

Therefore father age=2 * Rohith age.
So answer is 2.

For all your folks let me tell my method.

First he has given father's age is 3 times of rohit so if rohit age 1, then his fathers will be 1+3=4 i.e. the ratio will be 4:1.

Now after 8 years the ratio given is (2.5) :1.

Now 4-1=3.

2. 5-1=1. 5 for my method you have to keep the difference in two ratios must be same, so multiply (2.5) :1 with 2. It becomes 5:2 i.e. 5-2 = 3 the difference is same as of 4-1=3 now remember we got 5:2 after 8 years i.e 4:1.

8 years hence 5:2

Now 5-4=1= 8 years.

So that makes 40:16.

After further 8 years 48:24 i.e.TWISE (2 times).

At present, F and R.

R=R,

Father's age would 3 times more than Ronit's age
F=3R+R -> F=4R -----> (1)

After 8 years, F+8 and R+8.

Father would be 2 and half a times of Ronit's age
F+8=2 1/2(R+8).

Mixed fraction 2 1/2 = ((2*2)+1)/2 = 5/2.
F + 8=5/2(R+8),
2F+16 = 5R + 40,
2F-5R = 40 - 16,
2F-5R = 24 -------> (2)

Sub F=4R in (2).
2(4R)-5R = 24,
8R-5R = 24,
3R= 24.
R = 8 years, F = 32 years.
After further 8 years means;
F + 16 = 32 + 16= 48,
R + 16 = 8 + 16= 24,
Required ratio= 48/24 = 2.
Hence, After further 8 years, 2 times he would be of Ronit's age.

Let Ronit's age = x.

Father's age = x+3x (three times more than his son Ronit) = 4x.

After 8yrs.

Ronit's age = x+8.

Father's age = 4x+8.

But father will be two and a half times of Ronit's age so.

4x+8 = 5/2 (x+8).

x = 8.

Further after 8 years.

Ronit's age = x+8+8 = x+16.

Father's age = 4x+8+8 = 4x+16.

We know the value of x is 8 so putting value of x.

Now,

Ronit's age = x+16=8+16=24.

Father's age = 4x+16 = 4*8 +16 = 32+16 = 48.

Now we will calaulate the ratio of father's to ronit's age.

Father's age/ronit's age = 48/24 = 2.

Thus 2 is answer.

The sum of ages of family members (both children and parents) is 360 years.The total ages of children and parents are in the ratio 2:1 and the ages of wife and husband are in the ratio 5:7.What will be the age of husband?

a)60 b)77 c)75 d)70

Answer : d) 70

Solution :

Sum of ages is 360 years.The ratio of children and parents ages is 2:1.

Total age of parents = 360 x 1 / 3 = 120 years

Ratio of wife and husband age is 5:7. Therefore, the age of husband = 120 x 7 / 12 = 70

Hence the age of husband is 70 years.

any one explain me????? plz how it came.

As they said that father age is thrice,hence;

Let father present age = x,
Ronith age = y,

X = 3 * Y. => Y=X/3.

In the 2nd part, they mentioned that aftr 8yrs father age is 2.5 times of his son's age, hence
(X+8)=5/2(Y+8).

By substituting y=X/3, we get father present age i.e X=72yrs, Y=24yrs.

Then again he asked that how many times the difference between father and sons age further 8 yrs later;
Say later 8 yrs their difference is z. Hence
(X+8)=z(Y+8).

Putting X=72 and Y=24.
Then we get the difference is as z=2(approximately).

Consider son's age as 'x'
so they have said,

Father is aged three times more than his son
as per the statement, x+3x
after 8ys ,he would be 2 and a half times of his son
so, x+3x+8=x+8
4x+8=x+8
(4x+8)=5/2(x+8)
we get, 8x+16=5x+40 => 3x=24
x=8

after further 8 years,
so add 8 to the equation 4x+8+8=x+8+8
4x+16=x+16
so the ratio is, (4x+16)/(x+16) = 48/24
=> 2years

Got it friends?

I have a doubt if I'm trying to resolve this question by a short trick like:- if I assumed if son's age is 1 than father age should be 3times of his son
F ---- S.
3 ---- 1 then after 8 yrs it will be 5/2 it's mean
5 ---- 2.

Let's take the difference that is 2 &3, now to make equality in both our new ratio would be
9 F ---- 3S
10 F 4S, let's take the diff = 1.
1 = 8 ratio, now if I multiply in present ratio it's should be 72 and 24, that's mean F is 3 times of his son, but in your answer 2. Pls explain me.