Karen Morrison and Nick Hamshaw Solutions for Exercise 7: Exercise 17.7

The human population of Earth in August $2010$ was estimated to be $6.859$ billion people. In August $2009$, the population grew at a rate of $1.13\%$. Assuming this growth rate continues, estimate the population of the world in August of $2020$.

In $2010$ there were an estimated $1600$ giant pandas in China. Calculate the likely panda population in $2025$ if there is an annual growth in the population of $0.5\%$.

In $2010$ there were an estimated $1600$ giant pandas in China. Calculate the likely panda population in $2025$ if there is an annual decline in the population of $0.5\%$.

The value of a car depreciates each year by $8\%$. A new small car is priced at $\$11000$. How much will this car be worth in $8$ years.

Nils invests his savings in an account that pays $6\%$ interest compounded half yearly. If he puts $\$2300$ into his account and leaves it there for two years, how much money will he have at the end of the period?

The total population of a European country is decreasing at a rate of $0.6\%$ per year. In $2014$, the population of the country was $7.4$ million people. What is the population likely to be in $2020$ if it decreases at the same rate?

The total population of a European country is decreasing at a rate of $0.6\%$ per year. In $2014$, the population of the country was $7.4$ million people. How long will it take for the population to drop below $7$ million people?

A colony of bacteria grows by 5% every hour. How long does it take for the colony to double in size?