SOLUTION: The sum of the digits of a two digit counting number is 12 and the ratio of the units' digit to the tens digit is 1 to 2. What is the number?

Question 133606This question is from textbook Saxon Advanced Mathematics
: The sum of the digits of a two digit counting number is 12 and the ratio of the units' digit to the tens digit is 1 to 2. What is the number? This question is from textbook Saxon Advanced Mathematics

Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Let x = 10's digit
Let y = unit's digit
:
The sum of the digits of a two digit counting number is 12
x + y = 12
:
the ratio of the units' digit to the tens digit is 1 to 2.

Cross multiply
1x = 2y
:
Substitute 2y for x in the 1st equation
2y + y = 12
3y = 12
y = 12/3
y = 4 is the units digit
Then
8 = 10's digit
:
What is the number? It's 84

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