Let a Be the Set of All Strings of Decimal

question 17

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 begin with 774?

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Definitions:

Leased Department

A section within a retail store that is rented to an outside party.

Omni-Channel Retailing

A multi-channel approach to sales that seeks to provide customers with a seamless shopping experience whether they're shopping online from a mobile device, a laptop, or in a brick-and-mortar store.

Direct Selling

Retailing in which an independent representative of a company conducts retail and sales-related activities away from a fixed retail location, most often at consumers’ homes or place of business. Also known as direct retailing.

Specialty Food

Food that is of high quality and often unique in terms of origin, ingredients, or preparation, targeting a specific consumer market.