Can somebody tell me how to solve these kind of problems?

A certain forest covers an area of 1700km^2. Suppose that each year this area decreases by 5.75%. What will the area be after 8 years?

Sakura speaks 150 words per minute on average in hungarian, and 190 words per minute on average in polish. she once gave cooking instructions in hungarian, followed by cleaning instructions in polish. sakura pent 5 minutes total giving both instructions, and spoke 270 more words in polish than in hungaria how long did sakura speak in hungarian, and how long did she speak in polish? sakura spoke for minutes in hungarian and for minutes in polish