Question

По мосту за час проехало всего 40 автомобилей и двухколёсных велосипедов,а колёс у них было всего 100.Определи,сколько проехало автомобилей и сколько велосипедов. Если можно,то с решением.

Answer 1

Если бы автомобили имели по 2 колеса, то на земле стояли бы 80 колес:

2 · 40 = 80 (кол.)

Т.к. колес всего 100, то "лишние" колеса - это колеса автомобилей, их будет:

100 - 80 = 20 (кол.)

Т.к. эти "лишние" колеса - это колеса автомобилей и их по 2 у каждого, то автомобилей всего будет:

20 : 2 = 10 (авт.)

Тогда велосипедов будет:

40 - 10 = 30 (шт.)

Ответ: 10 автомобилей и 30 велосипедов.

Answer 2

Problem Analysis

We are given that a total of 40 vehicles, including cars and bicycles, crossed a bridge in one hour. The total number of wheels among these vehicles is 100. We need to determine the number of cars and bicycles that crossed the bridge.

Solution

Let's assume that the number of cars that crossed the bridge is C and the number of bicycles is B.

From the given information, we can form two equations:

1. The total number of vehicles: C + B = 402. The total number of wheels: 4C + 2B = 100 We can solve these equations simultaneously to find the values of C and B.

Solving the Equations

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

From equation 1, we can express C in terms of B: C = 40 - B

Substituting this value of C into equation 2, we get: 4(40 - B) + 2B = 100

Simplifying the equation: 160 - 4B + 2B = 100 -2B = -60 B = 30

Now, substituting the value of B back into equation 1, we can find the value of C: C + 30 = 40 C = 10

Answer

Therefore, the number of cars that crossed the bridge is 10, and the number of bicycles is 30.

Solution Verification

Let's verify our solution by checking if it satisfies both equations.

1. The total number of vehicles: C + B = 10 + 30 = 40 (satisfied) 2. The total number of wheels: 4C + 2B = 4(10) + 2(30) = 40 + 60 = 100 (satisfied)

Therefore, our solution is correct.

Conclusion

The number of cars that crossed the bridge is 10, and the number of bicycles is 30.