# How to divide the vibranium bar into 3 pieces? [duplicate]

You have a bar of vibranium and the Cap needs to use it (not used up or consumed) every day but he only needs 1/7th on the first day, 2/7th on the second day and so on for 7 days.

You have a vibranium knife that can cut through it for the Cap; however the knife is only good to make 2 cuts. You are very good and can cut perfectly.

How can you cut the vibranium bar into 3 pieces so that the Cap can get the perfect amount of vibranium for each day from 1 to 7?

## marked as duplicate by klm123, wbogacz, Peter Taylor, mdc32, kaineOct 28 '14 at 14:06

Make two cuts, leaving pieces of $1/7, 2/7, 4/7$ You can select pieces to get the amount required for each day.
• There is an old classic of paying for a hotel room with one link per day from a $63$ link gold chain. How few links can you cut so you can always make change. Any time I see a number $2^n-1$ I give binary a try. – Ross Millikan Oct 27 '14 at 20:45