Select the option for “?” that continues the pattern in the question.
3, -6, 12, 4, 20, ?
2nd term minus 1st term = -6-3 = -9
3rd term minus 2nd term = 12-(-6) = 12+6 = 18
4th term minus 3rd term = 4-12 = -8
5th term minus 4th term = 20-4 = 16
6th term minus 5th term = ?-20 = ?
The sequence of differences is -9, 18, -8, 16
That has the pattern: -9, 18, -8, 16, -7, 14, -6, 12, ...
So there must be a -7 after the last = sign
2nd term minus 1st term = -6-3 = -9
3rd term minus 2nd term = 12-(-6) = 12+6 = 18
4th term minus 3rd term = 4-12 = -8
5th term minus 4th term = 20-4 = 16
6th term minus 5th term = ?-20 = -7
?-20 = -7
Add 20 to both sides
? = -7+20
? = 13
Edwin