Q."Economics is a study of mankind in the ordinary business of life" - It is the statement of :

The central problems of an economy are the fundamental choices every society must make because human wants are unlimited but the resources to satisfy them are scarce and have alternative uses.

The problems (the 'what, how, for whom')

1. What to produce (and how much): which goods and in what quantities — consumer goods vs capital goods, guns vs butter. Choosing more of one means less of another.
2. How to produce: which technique — labour-intensive or capital-intensive — given resource availability and cost, to produce at least cost.
3. For whom to produce: how the output (national product) is distributed among the members of society — the problem of income distribution.

The two related problems

4. Efficient use of resources: are resources fully and best employed, or is there waste/unemployment? …