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GeekInterview.com > Placement Papers > Infosys > Challenging Puzzles
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Question: How old is the mother puzzle
Answer: The sum of their (father, mother and son) ages is 70. The father is 6 times as old as the son.
When the sum of their ages is twice 70, the father will be twice as old as the son.
How old is the mother? |
| June 06, 2008 01:16:34 |
#3 |
| aniace |
Member Since: June 2008 Total Comments: 4 |
RE: How old is the mother puzzle
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52
Let, in the initial part of the problem, x be the age of the son and y be the age of the mother then
x+6x+y=70
=>7x+y=70--------I
In the second part of the problem x` and y` be the respective ages afer t years
x`+2x`+y`=2*70=140
=> 3x`+y`=140--------------II
but we know that the second eqn is calculated after t years so we can write from the second eqn
7x+y+3t=140
70+3t=140
t=23.3333
II*7-I*3
and x-x`=y-y`=t
we get
(21*23)+(3*23)+4y`=770
y`=52.4 ~ 52
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