Find the 11th term of this sequence. - 10, 20, - 40, 80 ...

Okay just by looking at it the numbers go up By times 2

1). 10*2=20

2). 20*2=40

3). 40 * 2=80

4). 80*2 = 160

5). 160*2=320

6). 320*2=640

7). 640*2=1,280

8). 1,280*2=2,560

9). 2,560*2=5,120

10). 5,120*2=10,240

11). 10,240*2=20,480

But as we see every other number is negative

-10 20 - 40 80 - 160 320 - 640 1,280 - 2,560 5120 - 10,240 20,480

20,480 is your answer!