Question

Сколько пятизначных чисел, первая цифра который 3, а последняя 8?

Answer 1

Искомые пятизначные числа имеют вид 3abc8. Цифры a,b,c, очевидно, могут быть любыми. Существует по 10 способов выбрать значение каждой из них. Значит, всего таких пятизначных чисел будет 10*10*10=1000.

Answer 2

Answer:

There are 90 five-digit numbers where the first digit is 3 and the last digit is 8.

Explanation:

To find the number of five-digit numbers where the first digit is 3 and the last digit is 8, we can use the following approach:

- The first digit is fixed as 3. - The last digit is fixed as 8. - The remaining three digits can be any number from 0 to 9.

Using the multiplication principle, we can calculate the total number of possibilities: - The number of possibilities for the second digit is 10 (0-9). - The number of possibilities for the third digit is 10 (0-9). - The number of possibilities for the fourth digit is 10 (0-9).

So, the total number of five-digit numbers where the first digit is 3 and the last digit is 8 is 1 (for the fixed first digit) * 10 (possibilities for the second digit) * 10 (possibilities for the third digit) * 10 (possibilities for the fourth digit) * 1 (for the fixed last digit), which equals 1 * 10 * 10 * 10 * 1 = 1000.

However, we need to exclude the cases where the second, third, and fourth digits are all 0, as this would result in a four-digit number. Therefore, the total number of five-digit numbers where the first digit is 3 and the last digit is 8 is 1000 - 10 (for the excluded cases) = 990.

Therefore, there are 990 five-digit numbers where the first digit is 3 and the last digit is 8