BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

father son age problem

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 118
Joined: Fri Apr 18, 2008 4:58 am
Thanked: 1 times

father son age problem

by ifthyder » Thu Oct 09, 2008 9:40 pm
A father's age was three times that of his son five years ago,While five years hence the father will be twice as old as his son. Determine their present ages ?

A 13years , 10 years
B 40 years 16years
C 35 years 15 years
D 45 years 18 years
Top
Source: — Problem Solving |
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Thu Oct 09, 2008 9:51 pm
It should be C) 35 and 15
Top
Legendary Member
Posts: 833
Joined: Mon Aug 04, 2008 1:56 am
Thanked: 13 times

by vivek.kapoor83 » Thu Oct 09, 2008 9:56 pm
fastest way is takinng option and calculate.
lilke from d ..if u subtract -- 5 , that will give their age..3 times...true and if u add five,father will be of 40 and son 20, So both codn satisfy.No need to calculate.
Top
User avatar
Legendary Member
Posts: 871
Joined: Wed Aug 13, 2008 7:48 am
Thanked: 48 times

by stop@800 » Thu Oct 09, 2008 10:36 pm
vivek.kapoor83 wrote:fastest way is takinng option and calculate.
lilke from d ..if u subtract -- 5 , that will give their age..3 times...true and if u add five,father will be of 40 and son 20, So both codn satisfy.No need to calculate.
Good one :)
Top
Legendary Member
Posts: 1159
Joined: Wed Apr 16, 2008 10:35 pm
Thanked: 56 times

by raunekk » Thu Oct 09, 2008 10:59 pm
imo:c
Top
Master | Next Rank: 500 Posts
Posts: 154
Joined: Tue Aug 26, 2008 12:59 pm
Location: Canada
Thanked: 4 times

by canuckclint » Fri Oct 10, 2008 10:00 pm
I am not getting this one

two equations I set up

f-5 = 3(s-5)
f=2s

How do you get the answer algebraically?
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Fri Oct 10, 2008 10:12 pm
Let x be fathers present age and y be the sons present age

A father's age was three times that of his son five years ago:

x-5 = 3(y-5)
x-3y = -10 (1)

While five years hence the father will be twice as old as his son:

x+5 = 2(y+5)
x-2y = 5 (2)


Subtract 1 and 2:

x-3y = -10
x-2y = 5

-3y-(-2y) = -10 - 5

-y = -15

y =15

x=35

Hope this helps!
Top
Post new topic Post Reply
• Page 1 of 1