>>13308373The numbers of the left are being used as stand-ins for different numbers, but it's not stated what they actually mean. So we can only guess what they mean. In this case, their meaning appears to be increasing at a rate that goes up by one each time. The first line has each number as a stand-in for 10. The second has them as a stand-in for 15, an increase of five. The third line has them as a stand-in for 21, an increase of 6. The fourth line has them as a stand-in for 28, an increase of 7. It stands to reason that the next given line will have them as a stand-in for 36, an increase of 8.
>but 8+8!Isn't listed, and we can't just assume that it's implied. Furthermore, there's no logical connection between the numeric values of the numbers on the left as we're accustomed to them meaning, and what they mean in the case of this problem. So we simply assume that 9+9 is next in sequence for the pattern that we have observed.
