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Question 885532: a number consists of two digits of which tens digit exceeds the unit digit by seven. the number itself is equal to ten times the sum of the digits. find the number
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! IN WORDs:
The value of the number is
10 times the tens digit plus the ones digit, and
10 times the tens digit plus 10 times the ones digit
is ten times the sum of the digits.
The only way for that to happen is for the ones digit to be  .
Then, the tens digit is  .
THe number is  .
IN EQUATIONS:
 = the tens digit.
 = the unit digit.
So,
 = the sum of the digits.
 = the number itself.
The problem says that  and
 , and those are our equations.
<--->
From there, we cross out  on both sides of the equal sign (if allowed),
 <---> ,
or we say that we are subtracting from both sides of the equal sign,
 <---> or whichever way you write it in your class.
Then,  <---> <---> <--> <--> , and
 ---> ---> .
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