perplexus.info :: Numbers : One problem

One problem - many ways to solve... (Posted on 2017-12-21)

The problem below (Moscow Puzzles #313) can be solved in more than 4 ways,
(each d1 by itself) - using different approaches.

Find the number t and the digit represented by k in:
[3*(230+t)]^2=492,k04

List your ways of solving it.

No Solution Yet Submitted by Ady TZIDON

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Simple way to determine t

| Comment 4 of 6 |

Mod 10, the equation becomes 9*t^2 = 4

Then t^2 must equal 6 mod 10,

so t can only be 4 or 6.

Substitute both values in [3*(230+t)}^2 and evaluate.

This leads to the result that t can only be 4

Posted by Steve Herman on 2017-12-21 17:30:30

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