Answer me question no.2

Solution:
Let the sum be x.

C . I . = [x {\{1 + (\frac{15}{100})\}}^{3} - x] = \frac{4167}{8000} x S . I . = \frac{x \times 15 \times 3}{100} = \frac{9 x}{20} \Rightarrow C . I . - S . I . = 283.50 \Rightarrow \frac{567 x}{8000} = 283.50 \Rightarrow x = 4000

Thus, the sum amount is 4000.