Question

Из-заработанных летом денег студент 5/14истратил на покупку смартфона а3/7 на покупку велосипеда Сколько денег заработал студент если смартфон дешевле велосипеда на 280р.

Answer 1

Пусть х (руб.) заработал студент летом, тогда 5/14х (руб.) стоит смартфон, 3/7х (руб.) - велосипед. Уравнение:
3/7х - 5/14х = 280
6/14х - 5/14х = 280
1/14х = 280
х = 280 : 1/14
х = 280 * 14
х = 3920
Ответ: 3920 рублей. 

Answer 2

Solution:

To solve this problem, we can use the following steps:

1. Calculate the total amount of money spent on the smartphone and the bicycle. 2. Set up an equation to represent the relationship between the cost of the smartphone and the bicycle. 3. Solve the equation to find the amount of money the student earned.

Step 1: Calculate Total Money Spent

The student spent 5/14 of the money on the smartphone and 3/7 on the bicycle.

The total amount of money spent can be represented as: Total money spent = Money spent on smartphone + Money spent on bicycle

Step 2: Set Up Equation

Given that the smartphone is cheaper than the bicycle by 280 rubles, we can set up the following equation: Money spent on smartphone = Money spent on bicycle + 280

Step 3: Solve for Total Money Earned

We can use the equation from Step 2 to solve for the total amount of money the student earned.

Let's proceed with the calculations.

Calculation:

First, let's calculate the total amount of money spent on the smartphone and the bicycle.

Money spent on smartphone = 5/14 of the total money Money spent on bicycle = 3/7 of the total money

Now, we can set up the equation: 5/14 of the total money = 3/7 of the total money + 280

Solving for the total money earned: 5/14 of the total money - 3/7 of the total money = 280 (5/14 - 3/7) of the total money = 280

To simplify the equation, we can find a common denominator for the fractions.

Simplified Calculation:

The common denominator for 14 and 7 is 14.

Rewriting the fractions with the common denominator: (5/14 - 6/14) of the total money = 280 (-1/14) of the total money = 280

Now, we can solve for the total money earned: Total money earned = 280 / (-1/14) Total money earned = -280 * (-14) Total money earned = 3920 rubles

Answer:

The student earned 3920 rubles.

Therefore, the student earned 3920 rubles if the smartphone is cheaper than the bicycle by 280 rubles.