Mary is doing research on bird migration. Last week she counted 12 migratory birds in her yard. This week she counted 10. What was the percent decrease in birds this week? please show work!

Create a question with this scenario you could ask that could be answered only by graphing or using logarithm. david estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x.