SOLUTION: [ A two digit number is three times the sum of its digits. if 45 is added to the number, its digits are interchanged. what is the sum of the digits of the number ?

Question 821409: [ A two digit number is three times the sum of its digits. if 45 is added to the number, its digits are interchanged. what is the sum of the digits of the number ?

Answer by TimothyLamb(4379) (Show Source): You can put this solution on YOUR website!
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10y + x = 3(x + y)
10y + x + 45 = 10x + y
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put the system of linear equations into standard form
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10y + x = 3x + 3y
10y + x + 45 = 10x + y
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2x - 7y = 0
9x - 9y = 45
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https://sooeet.com/math/system-of-linear-equations-solver.php
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answer:
x= 7
y= 2
number = 27
sum of the digits = 9
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