275 historic buildings
The given concept will form an arithmetic sequence
Given the following parameters:
First-term "a" = 5
Number of terms "n" = 2003 - 1993
Number of terms "n" = 10
common difference = 5
Determine the sum of terms for the whole period
[tex]\begin{gathered} S_{10}=\frac{n}{2}(2a+(n-1)d) \\ S_{10}=\frac{10}{2}\lbrack2(5)+(10-1)\cdot5\rbrack \\ S_{10}=\frac{10}{2}\lbrack10+9(5)\rbrack \\ S_{10}=5\lbrack10+45\rbrack \\ S_{10}=5(55) \\ S_{10}=275historic\text{ building} \end{gathered}[/tex]Hence by the end of 2003, 275 historic buildings would be lost