Let a Be the Set of All Strings of Decimal

question 55

Short Answer

let A be the set of all strings of decimal digits of length five. For example, 00312 and 19483
are strings in A.
-How many strings in A have exactly one 5?

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Definitions:

MPS

Marginal Propensity to Save, which is the proportion of an increase in income that is saved rather than spent on consumption.

Saving

The process of setting aside a portion of current income for future use, typically in the form of investments or deposit accounts.

Disposable Income

Economic latitude for households in spending and saving after the removal of income taxes.

APS

Automatic positioning system; however, in an economic context, it often refers to the Average Propensity to Save, indicating the proportion of income that is saved rather than spent.