Question

Велосипедист и автобус стартовали из одного пункта. Скорость автобуса 45км/Ч а скорость велосипедиста 15км/Ч. Через какое время между ними будет 12 км?

Answer 1

Решение:
Скорость сближения велосипедиста и автобуса:
45-15=30(км/час)
Расстояние между ними 12км будет через:
12 : 30=2/5(час) или 2/5*60мин=120/5=24мин 

Answer 2

Problem Analysis

We are given that a cyclist and a bus start from the same point. The bus has a speed of 45 km/h, and the cyclist has a speed of 15 km/h. We need to determine the time it takes for the distance between them to be 12 km.

Solution

To solve this problem, we can use the formula: distance = speed × time.

Let's assume that the time it takes for the distance between the cyclist and the bus to be 12 km is t.

The distance traveled by the cyclist in time t is given by: distance_cyclist = speed_cyclist × t.

The distance traveled by the bus in time t is given by: distance_bus = speed_bus × t.

Since the cyclist and the bus start from the same point, the sum of their distances should be equal to 12 km: distance_cyclist + distance_bus = 12.

Substituting the values, we have: speed_cyclist × t + speed_bus × t = 12.

Now we can solve this equation to find the value of t.

Calculation

Substituting the given values: 15 km/h × t + 45 km/h × t = 12 km.

Simplifying the equation: 60 km/h × t = 12 km.

Dividing both sides of the equation by 60 km/h: t = 12 km / 60 km/h.

Simplifying the equation: t = 0.2 hours.

Answer

The time it takes for the distance between the cyclist and the bus to be 12 km is 0.2 hours.