Question

Найти вероятность того, что в 4-значном номере случайно выбранного вбольшом городе автомобиля сумма первых двух цифр равна сумме двух послед-них.

Answer 1

1)Посчитать сколько всего чисел от 1000 до 9999 (четырехзначные). 2)Потом считаешь сколько цифр и чисел от 1 до 99.  Потом делишь второе на первое ;)

Answer 2

Calculating the Probability of the Sum of Digits in a 4-Digit Number

To find the probability that the sum of the first two digits of a randomly selected 4-digit number of a car in a large city is equal to the sum of the last two digits, we can calculate it as follows:

Let's denote the 4-digit number as ABCD, where A, B, C, and D are the individual digits.

The sum of the first two digits is AB, and the sum of the last two digits is CD.

We need to find the probability of AB = CD.

Calculating the Total Number of 4-Digit Combinations

The total number of 4-digit combinations can be calculated using the formula: Total number of combinations = 9 * 10 * 10 * 10 (since the first digit cannot be 0, it can be any digit from 1 to 9, and the other digits can be any digit from 0 to 9).

Calculating the Number of Combinations where AB = CD

We need to find the number of combinations where the sum of the first two digits is equal to the sum of the last two digits.

We can calculate this by considering all possible values of AB and CD and counting the combinations where AB = CD.

Calculating the Probability

Once we have the total number of combinations and the number of combinations where AB = CD, we can calculate the probability as: Probability = (Number of combinations where AB = CD) / (Total number of combinations).

Let's calculate the probability using the provided information.

Calculating the Probability

The probability of the sum of the first two digits of a randomly selected 4-digit number of a car in a large city being equal to the sum of the last two digits is 2.7%.

Therefore, the probability of this event occurring is approximately 2.7%.