import matplotlib.pyplot as plt

# Data for population density and total population for each continent

continents = ['North America', 'South America', 'Europe']

population_density = [22.9, 23.8, 72.9] # People per square km (approx.)

total_population = [579024000, 430759000, 748219000] # Total population (approx.)

# Create the chart

fig, ax1 = plt.subplots(figsize=(8, 5))

# Plotting Population Density

ax1.bar(continents, population_density, color='skyblue', alpha=0.6, label="Population Density (per km²)")

ax1.set_xlabel("Continent")

ax1.set_ylabel("Population Density (per km²)", color='skyblue')

ax1.tick_params(axis='y', labelcolor='skyblue')

# Create a second y-axis for Total Population

ax2 = ax1.twinx()

ax2.plot(continents, total_population, color='orange', marker='o', label="Total Population (in billions)")

ax2.set_ylabel("Total Population (in billions)", color='orange')

ax2.tick_params(axis='y', labelcolor='orange')

# Add a title and show the chart

plt.title("Population Density and Total Population by Continent")

fig.tight_layout()

# Save the chart as an image file

plt.savefig("population_chart.png", dpi=300)

# Show the chart

plt.show()