Core idea
Economics studies choices when resources are limited. A budget helps compare what you want with what you can afford.
Solving method
Define an indicator before comparing it. Distinguish levels, growth rates, nominal values and inflation-adjusted values.
Worked example
You have ₹50. A pen costs ₹20 and a notebook costs ₹40. Can you buy both?
1. Both together cost ₹60.
2. ₹60 is ₹10 above the budget.
3. You must choose, save more, or find a less costly option.
Read the diagram
The two segments total ₹60, which exceeds the available ₹50 by ₹10. The budget is a constraint, not the same quantity as desired spending. Choosing one item can mean giving up another use of the money: an opportunity cost. In economics data, also distinguish prices from quantities and nominal changes from real changes.
Exam-style application
An economy's nominal output rises from 100 to 112 while its price index rises from 100 to 108. Approximate real growth is 12%-8%=4%; exact real growth=(1.12/1.08-1) x 100, about 3.70%. The approximation is useful for elimination, but exact choices require the ratio. Higher nominal output alone does not show an equal rise in production volume.
Common mistakes
Every choice may mean giving up another useful option. Disinflation is slower price growth, not necessarily falling prices. Business-awareness facts about companies, brands and leaders need date-specific verification.