Find all three-digit numbers in which the second digit is four times the first, and the sum of all three digits is 14.

Three-digit numbers are numbers from 100 to 999.

Numbers from 140 to 149 and from 280 to 289 are suitable for the second condition (since 1 * 4 = 4, 2 * 4 = 8, and 3 * 4 is already 12).

And the third condition: the sum of the digits is 14. You can check all the numbers selected according to the previous condition by the method of enumeration, but we will make it easier 1 + 4 = 5 from 14 subtract 5 we get 9, i.e. one of the numbers that fully meets the conditions of 149.2 + 8 = 10, 14 – 10 = 4. Therefore, we get the number 284.

Answer: 149, 284.



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