Aptitude - Problems on Ages - Discussion
Discussion Forum : Problems on Ages - General Questions (Q.No. 15)
15.
The age of father 10 years ago was thrice the age of his son. Ten years hence, father's age will be twice that of his son. The ratio of their present ages is:
Answer: Option
Explanation:
Let the ages of father and son 10 years ago be 3x and x years respectively.
Then, (3x + 10) + 10 = 2[(x + 10) + 10]
3x + 20 = 2x + 40
x = 20.
Required ratio = (3x + 10) : (x + 10) = 70 : 30 = 7 : 3.
Discussion:
79 comments Page 5 of 8.
Sri said:
2 decades ago
Hi sheikh,
In the problem,10 yrs ago father was thrice his son means
x-10=3(y-10) but how 3(x-10)=y-10 ?
In the problem,10 yrs ago father was thrice his son means
x-10=3(y-10) but how 3(x-10)=y-10 ?
Sri said:
2 decades ago
If we take x-10=3(y-10) and x+10=2(y+10) or 3(x-10)=y-10 and 2(x+10)=y+10 also we are getting ratio as 7:3
Priya said:
2 decades ago
How you got the value as x=20 while solving this 2 equ x=30 is coming how if possible please solve that 2 equ please.
Mallik said:
2 decades ago
@Bharat
It is simple. Here we are considering for after 10 years but the question is to find ratio of the present age.
So, (3x+10):(x+10) as x=20
Subs in the above equation, You will get 7:3.
It is simple. Here we are considering for after 10 years but the question is to find ratio of the present age.
So, (3x+10):(x+10) as x=20
Subs in the above equation, You will get 7:3.
Sheikh Moinuddin said:
2 decades ago
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.
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.
Bharath said:
2 decades ago
Can any one tell me how to derive the ratio?
Marpu Sruthi said:
1 year ago
Good session very clear explanations. Thanks all.
Siddharth said:
2 decades ago
Thanks nagu.
Shiv said:
9 months ago
@All.
Short trick formula =(10(3-1) + 10(2-1))3 - 2.
= 30 son age present.
10 years ago son's age =30 - 10 = 20.
The age of the father 10 years ago was thrice the age of his son,
20 * 3 = 60.
Father's present age = 60 + 10 = 70
Ratio father and son's age = 70 : 30 => 7 : 3.
Short trick formula =(10(3-1) + 10(2-1))3 - 2.
= 30 son age present.
10 years ago son's age =30 - 10 = 20.
The age of the father 10 years ago was thrice the age of his son,
20 * 3 = 60.
Father's present age = 60 + 10 = 70
Ratio father and son's age = 70 : 30 => 7 : 3.
Archi said:
2 decades ago
For 10 years ago it should be minus 10 give me reason please ?
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