MHB Find the Two-Digit Number: Exceeds by 4 and 1 Less Than Twice the Units Digit

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The problem involves finding a two-digit number where the tens digit exceeds the units digit by 4 and is also 1 less than twice the units digit. The correct interpretation leads to the tens digit being 9 and the units digit being 5, resulting in the number 95. A miscalculation occurred when the tens digit was incorrectly identified as the units digit, leading to confusion. Ultimately, the correct two-digit number is 95, confirmed by multiple calculations. The discussion emphasizes the importance of correctly interpreting the relationships between the digits.
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The tens digit of a certain two-digit number exceeds the units digit by 4 and is 1 less than twice the units digit. Find the two-digit number.

this is my solution,

let $x=$ tens digit, $x-4=$units digit.

$x=2(x-4)-1$ then, $x=9$ and $9-4=5$

the number is 59

but when I let $x=$ units digit and $x+4=$ tens digit I get the answer of 95.

can you tell me which one is correct?

tnahks!
 
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Re: digit problems.

I let $T$ be the tens digit and $U$ be the units digit, and so:

$$T=U+4=2U-1\implies U=5\implies T=9$$

And so the two digit number is $95$.
 
Re: digit problems.

paulmdrdo said:
let $x=$ tens digit... $x=9$ and $9-4=5$

the number is 59
No, it's 95.
 
Re: digit problems.

paulmdrdo said:
The tens digit of a certain two-digit number exceeds the units digit by 4 and is 1 less than twice the units digit. Find the two-digit number.

this is my solution,

let $x=$ tens digit, $x-4=$units digit.

$x=2(x-4)-1$ then, $x=9$ and $9-4=5$

the number is 59

but when I let $x=$ units digit and $x+4=$ tens digit I get the answer of 95.

can you tell me which one is correct?

tnahks!

In your solution you said: "let $x$ be the tens digit", and then solved for $x$ to obtain $x = 9$.

Thus your number is 9_ (ninety-something).

Solving for the unit digit, which you have as $x - 4$, you obtained: 5.

Thus your number is 95.

You solved it correctly, but misinterpreted your own solution.
 
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