Which pattern could have been used to create the sequence?
20, –40, 80, –160, 320
Multiply the previous term by –2
Divide the previous term by 2
Subtract 60 from the previous term.
Add –60 to the previous term.
If this is a multiple choice question, can't you just test each?
e.g. for (A): -160 x -2 = 320
Therefore, the answer is "multiply the previous term by -2"
To check that the rest are incorrect:
for (B): -160 /2 ≠ 320
for (C): -160 - 60 ≠ 320
for (D): -160 + -60 ≠ 320
NOTE: ≠ means 'not equal to'
The pattern used to create the sequence 20, -40, 80, -160, 320 is to multiply the previous term by -2.
To find this pattern, we can start with the first term, 20. If we multiply it by -2, we get -40, which matches the second term.
Continuing this pattern, if we multiply the second term, -40, by -2, we get 80, which matches the third term.
If we multiply the third term, 80, by -2, we get -160, which matches the fourth term.
Finally, if we multiply the fourth term, -160, by -2, we get 320, which matches the fifth term.
Therefore, multiplying the previous term by -2 is the pattern used to create the sequence.