please check:

The digit 3 is written at the right of a certain two-digit number thus forming a three-digit number. The new number is 372 more than the original two-digit number. What was the original two-digit number? my answer is 94?

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- Oct 10th 2009, 07:09 AMronaldjtwo-digit number
please check:

The digit 3 is written at the right of a certain two-digit number thus forming a three-digit number. The new number is 372 more than the original two-digit number. What was the original two-digit number? my answer is 94? - Oct 10th 2009, 07:16 AMDefunkt
Let x be the original two-digit number. Then, the new number is:

$\displaystyle 10x + 3$. Now, we know that $\displaystyle 10x + 3 = x + 372$

Solving this gives us:

$\displaystyle 9x = 369 \Rightarrow x = 41$

How did you arrive at 94? You should have easily noted that if you modify the number as stated you get 943, which is obviously not 372 more than 94. - Oct 10th 2009, 07:19 AMearboth
Let the original number be 10x +y with $\displaystyle x\in\{1, 2, ..., 9\}$ and $\displaystyle y\in\{0, 1, 2, ..., 9\}$

Then the 3-digit-number is 100x+10y+3.

According to the wording of the question you get:

$\displaystyle 100x+10y+3-372=10x+y$

$\displaystyle 10x+y=41$

The only possible value for x = 4 and y = 1. Thus the original number is 41. - Oct 10th 2009, 07:28 AMronaldj
- Oct 10th 2009, 07:35 AMronaldj
- Oct 10th 2009, 07:53 AMDefunkt
- Oct 10th 2009, 07:59 AMronaldjyou are sooh right!
My head hurts but you are right.

Tx for pointing out our mistake!