Total Weight of Packed Backpack

A backpack is packed with different items, and their weights are as follows:

• A laptop weighing 2.5 kg
• A set of textbooks weighing 4 kg
• A water bottle weighing 0.3 kg
• A lunch box weighing 0.2 kg
• A pencil case weighing 0.4 kg

If the backpack itself weighs 1.5 kg, what is the total weight of the backpack including all its contents?