Unitary method

The method in which the price of 1 article helps us in finding the price of any number of articles is known as the unitary method.

Note: if may be noted that: more articles will cost more Cost of any number of articles = (Cost of 1 article) * (number of articles)
Fewer articles will cost less
Cost of 1 article = Cost of a given number of articles/number of articles

Time and Work
If A can finish a piece of work in a day, the work done by A in 1 day =1/n

If A’s 1 day’s work= 1/n then the time is taken by A to finish the work = n days.