Identify the missing number in the number sequence.
Rule: multiply by 2 and add 10 each time.
5, 20, 50, ____, 230.

The correct answer is: 110

Step by step solution:
Rule: multiply by 2 and add 10 each time.
1st term: 5
2nd term: 5 x 2 + 10 = 20 (given)
3rd term: 20 x 2 + 10 = 50 (given)
4th term: 50 x 2 + 10 = 110
5th term: 110 x 2 + 10 = 230 (given)
Hence, option(b) is the correct option.