SOLUTION: David's age this year is a multiple of 5. Next year David's age will be a multiple of 7. How old is David now?

Question 866631: David's age this year is a multiple of 5. Next year David's age will be a multiple of 7. How old is David now?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
David's age this year is a multiple of 5. Next year David's age will be a multiple of 7. How old is David now?
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David's age now:: 5k
Next year his age is; 5k+1 = 7m
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Find an integer solution for "k" and for "m"::
Sequence of 5k+1:: 6,11,16,21
Sequence of 7m:::: 7,14,21
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Equation:
5k+1 = 21
5k = 20
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David is 20 now.
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Cheers,
Stan H.
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