Solution:
Concept- There are two places, ones and tens, when a number has two digits. Assume that the digit is always an x when solving questions, and then use the condition of the question to find more solutions.Let x now be the digit in the tens place.
The answer would therefore be
since the other digit is different by 3 in the question.Tens place
Once place
Number 
Since we know that to make a two-digit number, we multiply the digit at the tens place by 10, then add it to the digit at the one place by multiplying by 1.Consequently, the necessary number is
.Now, in accordance with the query, we swap the numbers, making the tens place equal to
and the once place equal to x.Number
is the newly produced number.New number is therefore
.The question now said that adding the previous and new numbers would result in the number 143.
put the value of 
,
Required number is 
Hence, [31]the correct answer is option 1.
