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Question 233319: I am an odd number. The sum of my digits is 10. I am less than forty. What numbers can i be?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! I am an odd number. The sum of my digits is 10. I am less than forty. What numbers can I be?
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If less than forty it is a 2-digit number.
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Let the number be 10t+u where t is the tens digit and u is the units digit.
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Equations:
10t+u < 40
t+u = 10
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u = 10-t
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Substitute into 10t+u<40 and solve for "t":
10t+10-t < 40
9t < 30
t < 30/9 = 3 1/3
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t is 1,2,or 3
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If t is 1, u = 9 giving you the number 19
If t is 2, u = 8 giving you the number 28
If t is 3, u = 7 giviing you the number 37
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Cheers,
Stan H.
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