Answer:
The most likely solution sought is 13:
Beginning with 3: subtract 9, add 18, subtract 8, add 16, subtract 7, add 14, etc. Each time, reduce the number subtracted by one, and double that number to add.
So, beginning with 3: 3-9 = -6, -6+2(9) = 12, 12-8 = 4, 4+2(8) = 20, 20-7 = 13, etc.
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Step-by-step explanation:
3, -6, 12, 4, 20, 11, 30
Explantion:
the difference between 3 and -6 is 9 same as 12 and 4 so you are going to take 9 away from 20 then you should end up will 11
the difference between -6 and 12 is 19 same as 4 and 20 so you are going to add 19 to 11 and you should get 30
I hope I answered your question, it should all be correct but if not please let me know
