Let me explain my answer: 9

This is an old and ridiculous question because the wording of the question is ridiculuos, even though the concept is interesting.

Here's the interesting part: any single digit number multiplied by 9 will always result in a sum of 9 when the two numbers are added together, e.g.,

2 X 9 = 18 = 1+8 = 9

3 X 9 = 27 = 2+7 = 9

4 X 9 = 36 = 3+6 = 9

....

9 X 9 = 81 = 8+1 = 9

The problem is the question. It is not written correctly and should not have been asked.

Perhaps the man who wrote the question did not give an answer because the wording of the question is incorrect. It might have made sense if it asked "what is the product of the sum (or what sum is produced) of the two digits in the product (multiplication) of 6 and 9 becuase 6X9=54=4+5=9

Because the wording of the question was incorrect, no one could get the answer... silly question, don't you agree?

product. (Mathematics)

 The number or quantity obtained by multiplying two or more numbers together.

6x9= 54

other meanings:

 A scalar product.

 A vector product.

The product of 6 and 9:

6 * 9 = 54

9

I went through the 3 pages to find out what was the answer and nothing!