# Define the function that adjusts inventory levels
def update_inventory(inventory, items_sold):
    # Iterate over each item in the dictionary
    for product, quantity_sold in items_sold.items():
        # Decrease the inventory by the quantity sold for each product
        inventory[product] -= quantity_sold

# Inventory dictionary
inventory = {
    "apples": 50,
    "bananas": 75,
    "oranges": 100
}

# Items sold dictionary
items_sold = {
    "apples": 5,
    "oranges": 15
}

# Update the inventory based on items sold
update_inventory(inventory, items_sold)

# Display the updated inventory
print("Updated inventory:", inventory)