Question

ПОМОГИТЕ ПОЖАЛУЙСТА! СРОЧНО! 30 БАЛЛОВ! Александр, Борис и Виктор решили 80 задач, причем каждый из них решил 40 задач. Назовем задачу "трудной", если ее решил только один из мальчиков, и "легкой", если ее решили все три мальчика. На сколько "трудных" задач больше, чем "легких"?

Answer 1

60+60+60=180-всего решено задач
100-80=20-решили легких задач
60-20=40-решили легких задач
40-20=20-на столько трудных задач больше ,чем легких

Answer 2

Problem Analysis

We are given that Alexander, Boris, and Victor solved a total of 80 problems, with each of them solving 40 problems. We need to determine the difference between the number of "difficult" problems, solved by only one of the boys, and the number of "easy" problems, solved by all three boys.

Solution

To solve this problem, we need to find the number of "difficult" problems and the number of "easy" problems.

Let's assume that the number of "difficult" problems solved by only one of the boys is x, and the number of "easy" problems solved by all three boys is y.

According to the given information, each boy solved 40 problems, so the total number of problems solved by all three boys is 40 + 40 + 40 = 120.

We can write the following equation to represent the total number of problems: x + y + y + y = 120

Simplifying the equation, we get: x + 3y = 120

We also know that the total number of problems solved by all three boys is 80, so we can write another equation: x + y = 80

Now we have a system of equations: x + 3y = 120 x + y = 80

Solving this system of equations will give us the values of x and y.

Solution Steps

1. Subtract the second equation from the first equation to eliminate x: (x + 3y) - (x + y) = 120 - 80 2y = 40 y = 20

2. Substitute the value of y into the second equation to find x: x + 20 = 80 x = 60

3. Calculate the difference between the number of "difficult" problems (x) and the number of "easy" problems (y): Difference = x - y = 60 - 20 = 40

Answer

The number of "difficult" problems is 40 more than the number of "easy" problems.