How many different zip codes can be made with the digits 0 9 if no - ProProfs Discuss

# How many different zip codes can be made with the digits 0-9 if no digit is used more than once and the first digit is not 0? A zip code contains 5 digits.

A. 9 x 8 x 7 x 6 x 5
B. 9 x 9 x 8 x 7 x 7
C. 9 x 9 x 7 x 6
D. 9 x 9 x 8 x 7 x 6

This question is part of Pre NET 2015 Engineering by Taleem Tutor
Asked by Ejazmoaz, Last updated: May 28, 2020

#### Danny R. Glover

Danny R. Glover, Editor, New York City

The correct answer to this question is D, 9 x 9 x 8 x 7 x 6. Being that the first digit isn't 0, the first position has 9 possible choices. The second position allows 0, which allows for 9 possible choices as well. From there, the third allows eight, the fourth allows 7, and the fift allows 6 possible choices.

This algebra question can be solved by reasoning, as well as using the permutation formular. This formula lists objects in order of importance. It is used when counting with the order matters and when it can be counted without replacements.

The best answere is d because in a 9 is repeated

Why

#### John Smith

John Smith

9 x 9 x 8 x 7 x 6

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