The length, width and height of a cuboid packing box are 20cm, 10cm and 6cm respectively. Now, tie it up with ribbon. The ribbon at the joint is 15cm long. How long is the ribbon

The length, width and height of a cuboid packing box are 20cm, 10cm and 6cm respectively. Now, tie it up with ribbon. The ribbon at the joint is 15cm long. How long is the ribbon

You mean a self crossed bundle?
If it is
Then the length of the rope = 20 * 2 + 10 * 2 + 6 * 4 + 15 = 99cm

The figure below is a gift box, 6cm long, 5cm wide and 4cm high. If the ribbon is 15cm at the joint, how long is the ribbon?

What about the picture? How to tie the ribbon? I can't give you the answer without the picture. OK, let me guess first. The first standard packing method
The formula is 15 + 4 times the height, 4 + 2 times (5 + 6) = 53cm
The reason is that people who have seen the gift wrapping know why it is
15 + 3 times (4 + 5 + 6) = 60cm
How can I tell you the answer if you don't give me a picture

The shop assistant tied a 30cm long, 15cm wide and 10cm high shoe box with packing rope. The joint is 20cm. How long does it take to tie this shoe box?

30 × 2 + 15 × 2 + 10 × 4 + 20 = 60 + 30 + 40 + 20, = 150 (CM); a: it needs at least 150 cm long rope to tie this shoe box