Question

BRAINLIEST AND FIVE STARS FOR CORRECT ANSWER

Answer 1

The full sequence from 3 to 21 is...

3, 5, 7, 9, 11, 13, 15, 17, 19, 21

Now first add 3 and 5 to get 8. Then 8 and 7 to get 15. After, add 15 and 9 to get 24 and furthermore.

(24+11=35 --> 35+13=48 --> 48+15=63 --> 63+17=80 --> 80+19=99 --> 99+21=120)

So I believe the sum of the sequence is 120
 
I hope this helps!