The next term should be 15.
first ignore the 1st, 3rd, 5th, 7th term, they're just adding 1. and the other terms left are the multiplies of 3. 6,9,12,15...
6.3 - (4.9 - 7.8)
6.3 - 4.9 + 7.8
1.4 + 7.8
9.2
Answer:
D) 9.2
Its faster in adding isn't always right when you are multiplying numbers