Chapter 8.5, Problem 22E

(a)

To determine

To find: the number of ZIP codes consisting of five digits followed by the four additional digits.

Answer to Problem 22E

The number of ZIP codes consisting of five digits followed by the four additional digits are 1000000000.

Explanation of Solution

Given information:

In 1983, in order to identify small geographic segments within a delivery code, the post office began to use an expanded ZIP code called ZIP+4, which is composed of the original five digit code plus a four digit add on code.

Calculation:

First digit can be any one number from 0 to 9.

Second digit can be any one number from 0 to 9.

Third digit can be any one number from 0 to 9.

Fourth digit can be any one number from 0 to 9.

…

9^th digit can be any one number from 0 to 9.

The possible numbers of digit ZIP codes consisting five numbers plus a four digit are:

  $\begin{array}{l}=10\times 10\times 10\times 10\times 10\times 10\times 10\times 10\times 10\\ =1000000000\end{array}$

(b)

To determine

To find: the number of ZIP codes consisting of five digits followed by the four additional digits when the first number of the five digit code is 1 or 2.

Answer to Problem 22E

The number of ZIP codes consisting of five digits followed by the four additional digits when the first number of the five digit code is 1 or 2 are 200000000.

Explanation of Solution

Calculation:

Second digit can be any one number from 0 to 9.

Third digit can be any one number from 0 to 9.

Fourth digit can be any one number from 0 to 9.

…

9^th digit can be any one number from 0 to 9.

The possible numbers of ZIP codes consisting five digit numbers plus a four digit when the first digit is 1 or 2 are:

  $\begin{array}{l}=2\times 10\times 10\times 10\times 10\times 10\times 10\times 10\times 10\\ =200000000\end{array}$