Question

На детской площадке катались дети на двух и трёхколесных велосипедах. Сколько и каких велосипедов было на площадке, если всего было 21 колесо и 8 велосипедов? Условие, решение и ответ плииз

Answer 1

Двуколёсных:3 велосипеда

Трёхкалёсных:5 велосипедов
1)2×3=6 (колёс)
2)21-6=15 ( колёс )
3 ) 15 : 3 = 5 ( 3-ёх колёсных велосипедов )
4)6:2=3 ( 2-ух колёсных велосипедов)

Answer 2

Problem Analysis

We are given that children were riding on two- and three-wheeled bicycles on a playground. We need to determine the number and types of bicycles on the playground, given that there were a total of 21 wheels and 8 bicycles.

Solution

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

Since each two-wheeled bicycle has 2 wheels and each three-wheeled bicycle has 3 wheels, we can create the following equation based on the given information:

2x + 3y = 21 ---(Equation 1)

We also know that the total number of bicycles is 8:

x + y = 8 ---(Equation 2)

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

To solve the system of equations, we can use the substitution method. Let's solve Equation 2 for x:

x = 8 - y

Now substitute this value of x into Equation 1:

2(8 - y) + 3y = 21

Simplify the equation:

16 - 2y + 3y = 21

Combine like terms:

y + 16 = 21

Subtract 16 from both sides:

y = 5

Now substitute the value of y back into Equation 2 to find x:

x + 5 = 8

Subtract 5 from both sides:

x = 3

Therefore, there were 3 two-wheeled bicycles and 5 three-wheeled bicycles on the playground.

Answer

There were 3 two-wheeled bicycles and 5 three-wheeled bicycles on the playground.

Verification

Let's verify our answer by checking if it satisfies the given conditions.

The total number of wheels is 21. Since each two-wheeled bicycle has 2 wheels and each three-wheeled bicycle has 3 wheels, we can calculate the total number of wheels using our answer:

Total number of wheels = (2 * number of two-wheeled bicycles) + (3 * number of three-wheeled bicycles) = (2 * 3) + (3 * 5) = 6 + 15 = 21

The total number of wheels matches the given information, so our answer is correct.

Conclusion

There were 3 two-wheeled bicycles and 5 three-wheeled bicycles on the playground. This information was obtained by solving a system of equations based on the given conditions.