Answer:
1. Giving a tip to a waiter sometimes after two fast
services, other times after every fast services,
etc……………………….
2. Praising a student every time when he finishes
his home work in the evening …………………
3. Buying new clothes for a child every six months
provided he obtains an average of 80% or more
in school work…………………..
4. Giving bonus to workers sometimes every year,
other times every two years , and so on provided
they meet a specific target………………………