Step-by-step explanation: Begin by studying the pattern.
Notice that the 1 + 1 is 2, 2 + 3 is 5, 5 + 5 is 10, and 10 + 7 is 17.
So thus far, we're adding 1, 3, 5, and 7. Notice that each of these numbers have a difference of 2 so we would add 9 to get to next number and so on.
