We have a 100-meter piece of ribbon.
If it takes one second to cut it into a 1-meter strip how long would it take to cut the entire ribbon into 1-meter strips?
Number of cuts will be 100-1=99 as the last strip doesn't need to be cut
Total time required is 99 seconds=1 min 39 seconds
If it takes 4 minutes to cut a log into 4 pieces, how many minutes will it take to cut a log into 3 pieces?
Assume all cuts are parallel, and cuts are done sequentially (not simultaneously).
If it took eight men ten hours to build a wall, how long would it take four men to build it?