Question

Определите количество семизначных телефонных номеров, начинающихся с 432 и заканчивающиеся на 3 и 5 ???

Answer 1

Должно быть как-то так

Answer 2

Calculation of Seven-Digit Phone Numbers Starting with 432 and Ending with 3 and 5

To determine the number of seven-digit phone numbers that start with 432 and end with 3 or 5, we need to consider the possible combinations for the remaining four digits in the middle.

Since we are looking for seven-digit numbers, the first digit is fixed as 4, the second digit is fixed as 3, and the last digit is fixed as either 3 or 5. This leaves us with four digits in the middle that can be any number from 0 to 9.

To calculate the number of combinations, we need to multiply the number of possibilities for each digit together.

- The first digit is fixed as 4. - The second digit is fixed as 3. - The third, fourth, fifth, and sixth digits can be any number from 0 to 9, giving us 10 possibilities for each digit. - The last digit is fixed as either 3 or 5.

Therefore, the total number of combinations is:

4 (fixed) * 3 (fixed) * 10 * 10 * 10 * 10 * 2 (fixed) = 240,000

So, there are 240,000 seven-digit phone numbers that start with 432 and end with 3 or 5.