SOLUTION: The sum of the digits of a positive 2-digit number is 13 If twice the first digit is 1 less than the second digit, what is the two digit number?

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Question 364998: The sum of the digits of a positive 2-digit number is 13 If twice the first digit is 1 less than the second digit, what is the two digit number?
Answer by amoresroy(361) About Me  (Show Source):
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The sum of the digits of a positive 2-digit number is 13 If twice the first digit is 1 less than the second digit, what is the two digit number?
Let x = the unit's digit as the first digit
y = the ten's digit as the second digit
1st equation
x+y = 13
2nd equation
2x = y-1
y = 2x+1
Substituting y=2x+1 in equation 1 gives us
x+(2x+1)=13
3x =13-1
x =4
Then y = 13-4=9
The 2-digit number is 94