Correct Answer: 450.187
Explanation:
Here the given number series 3, 10.5, 36.75, 128.625, ? follows a pattern that
3
3 x 3.5 = 10.5
10.5 x 3.5 = 36.75
36.75 x 3.5 = 128.625
128.625 x 3.5 = 450.187
Hence the next number in the given number series is 450.187.