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:
77 comments Page 2 of 8.
Gimid-pussi said:
5 years ago
Required ratio = (3x + 10) : (x + 10) = 70 : 30 = 7 : 3.
Anyone explain this step in detail.
Anyone explain this step in detail.
(1)
Ayushi gujarati said:
6 years ago
Here is my solution;
Son's present age = x.
Father's present age=y.
10 years ago
(y-10) = 3(x-10)
y-10=3x-30
y-3x=-20 --------> eq 1
10 years after
(y+10)=2(x+10)
y+10=2x+20
y-2x=10 --------> eq2.
now
y-3x=-20,
y-2x=10.
10(y-3x)=-20(y-2x).
10y-30x=-20y+40x.
10y+20y=40x+30x.
30y=70x.
So now y:x = 3:7.
Son's present age = x.
Father's present age=y.
10 years ago
(y-10) = 3(x-10)
y-10=3x-30
y-3x=-20 --------> eq 1
10 years after
(y+10)=2(x+10)
y+10=2x+20
y-2x=10 --------> eq2.
now
y-3x=-20,
y-2x=10.
10(y-3x)=-20(y-2x).
10y-30x=-20y+40x.
10y+20y=40x+30x.
30y=70x.
So now y:x = 3:7.
(14)
Pammy said:
6 years ago
@Archi simple why they have taken minus means 3x is 10 year ago.
3x+10 present age.
3x+10 +10 means 10 years after present age.
3x+10 present age.
3x+10 +10 means 10 years after present age.
(1)
Rachana said:
6 years ago
@Shubham.
Actually, it is not right.
Because initially the age of the boy and his dad are 'x' & '3x' respectively.
10yrs ago it was the case.
Presently, their ages are (x+10) & (3x+10) respectively.
Actually, it is not right.
Because initially the age of the boy and his dad are 'x' & '3x' respectively.
10yrs ago it was the case.
Presently, their ages are (x+10) & (3x+10) respectively.
SHUBHAM said:
7 years ago
Ago means subtract so, X+10-10 this statement may be right.
Rohini Priya said:
7 years ago
Here they considered ages 10 years ago 3x and x, these are not present ages.
Since we solve all problems by having present ages we convert them to the present age.
So the present ages will be 3x+10 and x+10.
Since we solve all problems by having present ages we convert them to the present age.
So the present ages will be 3x+10 and x+10.
(1)
Iba Krish said:
7 years ago
Very useful @Nagu.
Mannai shakthi said:
7 years ago
Please give detailed answer and explanation about this sum. How will add the ages when it is mentioned as ago?
Namgay said:
8 years ago
Why to take 10 in order to find the present ratio?
Paritosh said:
8 years ago
Let Akash age is x+4, Akansha age is x.
from the given relation 4x = 3(x+4)
now x=12,x+4=16
Their combined age is 12+16=28.
from the given relation 4x = 3(x+4)
now x=12,x+4=16
Their combined age is 12+16=28.
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