Originally Posted by

**mohammadfawaz** Hello,

I think the books contains an error: either in the question or in the answer. If the question is as it is, the answer is definitely 100,000,000. Trust me! The answer cannot be $\displaystyle 3.3 \times 10^7$ unless the decrease is 75% per year and not 25% because then the answer would be $\displaystyle \frac{25,000,000}{1-0.25} = 3.333\times 10^7$ which is fairly close to the answer of the book. The method we are using is correct so be confident and use 100,000,000 as an answer.

Regards,