Aptitude - Problems on Ages - Discussion

Very helpful. Thanks, everyone for explaining the answer.

best tricks for this type of question;

5 :4.
11:9.

4(years Anand age question ask Anand age then multiply)*3(years hence)*2(11-9=2)/(5*9 cross multiply) - (11*4 cross multiply) = 24.

So, the answer = 24.

Always we have to assume (in ratio problem): X.

And according to the question the present age is = 5X/4X.

And;
According to the question 3 year hence so we can write in form as 5X + 3/4X + 3.

And our next step will be according to the question said the ratio will become 11/9.
So we can write'
5x+ 3/4x+3 = 11/9.

After solving equations
45x + 27 = 44x + 33 and then;
X = 6. After solving that equations
And put the value in Anand age so;
The question will be;
4x = 4*6 = 24 that is final answer.

We can also use the formula qt(r-s)/ps-qr where p,q,r,s are given ratios 5:4, 11:9 respectively and t= years given.

4(3)(11-9)/5(9)-4(11) = 12(2)/45 - 44 = 24.

Formula: The ratio of present ages of A and B is p:q and after t years, the ratio is r:s, then
A's present age = pt(r-s)/ps-qr.
B's present age = qt(r-s)/ps-qr.

At last, they have multiplied with 4 that is 4x because they have considered the present age of Anand is 4x we have been asked to find present age of Anand that's why we have multiplied with 4 and we know x=6.

So, 4 * 6 = 24.

Here, the present ratio is 5: 4, 5x:4x then after 3years means 5x+3/4x+3equalto 11/9 if we cross multiply this we got X value is 6 then substitute in 4x then 4*6 then 24.

According to me, it is X=6.

Why multiply by 4(5:4)?

When the current ratio leads to multiplying by 9 (11:9), where they have asked to find the present age of Anand after 3years.

Here 5:4 is taken with x variable 5X/4X but why the ratio after 3 years 11:9 is not taken with variable x as 11X/9X. Please clarify.

The ratio of their present age is 5:4.
After 3 years, the ratio become 11:9.

Now, the difference is not equal which is 6:5 this ratio should be equal whenever to ask such a question. When equal their ratio new ratio is;
10:8
And 11:9.
Then; 1=3.
And asked is 8*3=24.

@ Sonu.

The ratio means short answer of fraction eg: 20/25 short answer is 4/5 so we can write in the form of 4x/5x.

~ the fraction of numerator and denominators are divided by the same number that's called x
P/Q=3x/4x(presentratio) Q's present age is 20.
4x =20 ; => x= 5.
after 5 years, (3x+5/4x+5) = 20/25.
Then the ratio is 4/5.