NCERT Solutions for Class 9th Social Science Chapter 8 Opportunity cost in everyday life — LET'S EXPLORE

This is a short interview, and the answer must end with a clearly named opportunity cost — the specific thing given up, not a vague “money”.

Method. Ask three questions and write the replies down.

1. What did you decide to buy this week, and what else were you considering? — this gives you the two alternatives.
2. Why did you pick one over the other? — this gives the reason.
3. What did you have to drop or postpone because of it? — this is the opportunity cost, and it is the answer to the question.

Then state it in one sentence of the form: “The opportunity cost of ___ was ___.”

Sample answer: My mother had ₹2,000 to spend at the end of the month and two uses in mind — repairing our old ceiling fan, or buying a pressure cooker to replace the one that leaks. She chose the fan repair, because summer had started and the fan is used by everyone in the house all day, while the leaking cooker still works, only slowly. The opportunity cost of repairing the fan was the pressure cooker, which now has to wait until next month — along with the cooking gas and the time the new cooker would have saved every day.

My father described a different kind of choice. He travels to work either by bus (₹20 and about an hour) or by shared auto (₹50 and about half an hour). On ordinary days he takes the bus. The opportunity cost of saving ₹30 is the half hour he loses, and on days when he must reach early that half hour is worth more than ₹30 to him, so he takes the auto. The same person makes opposite choices because the value of what is given up changes.

Yes — time is a scarce resource, and by the chapter's own test it is a particularly strict one. A resource is scarce when it is limited in quantity and has alternative uses. Time is limited to 24 hours a day for everybody, and those hours can be put to many competing uses. So every hour spent one way is an hour that cannot be spent another way.

How the decision is actually made. I first fix the hours that are not really mine to choose — school and sleep. Then I rank what is left by two tests: what has a deadline, and what I would regret losing. Homework due tomorrow goes first because postponing it costs marks. Play and helping at home come next, because they cannot be stored up. Television and the phone come last, because they expand to fill whatever time is left if I do not limit them.

The opportunity cost of an hour. If I watch television for an hour instead of revising, the cost is not “an hour” — it is the revision I did not do and the marks that follow from it. Stated that way, the choice becomes easier to make honestly.