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Age

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by heshamelaziry » Sun Nov 29, 2009 5:40 pm
Seven years ago Bob was k times as old as Ann. If Ann is now 11 years old, what is Bob's present age in terms of K ?

7 + 4K

11/k + 7

11- 7/k

11 - k/7

4k - 7


OA is A I would like to know why this does not work :

B - 7 = KA ----> B - 7 = K( 11 - 7) --------> B = 6K + 7 !!!!!!!!
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Source: — Problem Solving |

by deagez » Sun Nov 29, 2009 6:34 pm
the reason it does not work is because 11k-7k is 4k not 6k
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by heshamelaziry » Sun Nov 29, 2009 6:51 pm
My translation was correct but arithmetic is wrong.
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by kpitchfo » Sun Nov 29, 2009 7:55 pm
Careful on your first algebraic equation. It should be:

(b-7)=k(a-7)
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by heshamelaziry » Sun Nov 29, 2009 8:05 pm
kpitchfo wrote:Careful on your first algebraic equation. It should be:

(b-7)=k(a-7)
A is 11 because the is the age now
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by Gmatter2.0 » Mon Nov 30, 2009 7:43 pm
Diagramming the Qn:

______Now-7_______Now_____________
| |
|Bob | x-7 ------------- x
|___ |______________________________
| |
|Ann | y-7 ------------- y
|___ |______________________________

Given that y=11

Seven years ago Bob was k times as old as Ann
x-7=k(y-7)
x=7+k(y-7)
=7+k(11-7)
=7+4k
A is the correct Choice..
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