Create a story background with a company sales situation or a population situation in certain area. The

story shoud include $24$ consecutive time periods with a beginning value and reasonable percentage

changes for each period. $24$ percentage changes should have at least three different rates and at least one

negtive rate. Reasonable rates whould be between $-10\%$ and $20\%.$ After the story and data are built up$,$

please perform the following operations.

a$.$ Calculate the ending value after the $24$ time periods.

b$.$ Calculate the average percentage change for the $24$ periods using the percentage changes provided for

each period.

c$.$ Calculate the average percentage change for the $24$ periods using the beginning value provided in the

story background and the ending value developed from part a$.$

Note: You should notice that your calculation result from part $b$ and $c$ should be the same. If they are not the same, some mistakes might have been made in your calculation. If they are not the same, some mistakes might have been made in your calculation.