Answer:
381.
Explanation:
This is a geometric sequence.
3rd term = ar^2 = 12
6th term = ar^5
6th term / 3rd term
= 96/12 = 8 so:
8 = ar^5 / ar^2
8 = r^3
r = 2 (the common ratio).
The first term = ar^2/ r^2
= 12/ 4
= 3.
The 7th term = 3*2^6
= 192.
For the sum of all the terms less than 250 we need the sum of the first 7 terms.
This = 3* [(2^7 - 1 )/ (2 - 1)]
= 381.