Aptitude - Problems on Ages - Discussion

We can do this problem by this method:
let the age of the son be x
let the age of the father be y
10 years ago
x-10=y-10
father was 3times the son so,
3(x-10)=y-10
3x-30=y-10
3x-y=20........1 equation
10 years hence
x+10=y+10
father was 2times that of the son
2(x+10)=y+10
2x+20=y+10
2x-y=-10........2equation
now solve the equation 1 and 2.

Can any one tell me how to derive the ratio?

Thanks nagu.

Good session very clear explanations. Thanks all.

For 10 years ago it should be minus 10 give me reason please ?

Given, father's age(x) = 3(y)son's age.

y = x/3.

Original equation is, 10 years ago x-10 = 3(y-10).

= 3(x/3-10).....(A).

Given, after 10 years father's age(x) = 2(y)son's age.

y = x/2.

Original equation is, after 10 years x+10 = 2(y+10).

= 2(x/2+10).........(B).

Equating (A) & (B) for present ages, 3(x/3-10) = 2(x/2+10).

x = 80.

y = 40.

These are the ages after 10 years.

Hence, for present ages remove 10 years from both 70:30 or 7:3.

@Ramu:
Now Assume Father age is x and Son age is y

According to first statement : Father's age is three years more than three times the son's age
x=3y+3
So x-3y=3 --->1

According to second statement : After three years, father's age will be ten years more than twice the son's age
x+3=2(y+3)+10
x-2y=13 ---->2

substitute 1 & 2:
x=33
y=10

So father's present age is 33.

Thank you god bless you all.

VERY TRICKY!!!!!!

Thanks nagu.

Can anybody tell the answer to this question?

In 1996, Raju age was equal to the numbers formed by the last two digits of his birth year. This was same for his grandfather also. Find the difference between their ages.