Question

Общее число двухколёсных и трёхколёсных велосипедов равно 5, а число их колёс-12. Сколько двухколёсных и трёхколёсных велосипедов? составьте краткую запись и реши задачу.

Answer 1

Пусть
х велос.- трехколесных
у велос. - двухколесных

{х+у=5
{3х+2у=12 ⇔

{х=5-у
{3(5-у)+2у=12 ⇔

{х=5-у
{3у-2у=3 ⇔

{х=5-у
{у=3 (велос). - двухколесных
5-3=2(велос). - трёхколёсных

Answer 2

Problem Analysis

We are given that the total number of two-wheeled and three-wheeled bicycles is 5, and the total number of wheels is 12. We need to determine the number of two-wheeled and three-wheeled bicycles.

Solution

Let's assume the number of two-wheeled bicycles is x and the number of three-wheeled bicycles is y.

From the given information, we can form the following equations: 1. The total number of bicycles: x + y = 5. 2. The total number of wheels: 2x + 3y = 12.

We can solve this system of equations to find the values of x and y.

Solving the System of Equations

To solve the system of equations, we can use the method of substitution or elimination. Let's use the method of substitution.

From equation 1, we have x = 5 - y.

Substituting this value of x into equation 2, we get: 2(5 - y) + 3y = 12.

Simplifying the equation: 10 - 2y + 3y = 12, 10 + y = 12, y = 12 - 10, y = 2.

Now, substituting the value of y back into equation 1, we get: x + 2 = 5, x = 5 - 2, x = 3.

Answer

Therefore, the number of two-wheeled bicycles is 3 and the number of three-wheeled bicycles is 2.

Verification

Let's verify our solution using the given information.

The total number of bicycles is 3 + 2 = 5, which matches the given information.

The total number of wheels is 2(3) + 3(2) = 6 + 6 = 12, which also matches the given information.

Therefore, our solution is correct.

Summary

The number of two-wheeled bicycles is 3 and the number of three-wheeled bicycles is 2.