Question

Расстояние между городами A в город B равно 72 км.Из города A в город выехал велосипедист со скоростью 9 км/ч. Через 3ч после отъезда велосипедиста из города A в город B выехал мотоциклист,который догнал велосипедиста на расстоянии 31,5 км от города A.На каком расстоянии от города B будет велосипедист,когда туда приедет мотоциклист?Напишет пожалуйста не только ответ но и решение.

Answer 1

 3*9 = 27км проедет велосипедист за 3 часа
31,5-27 = 4,5км проедет велосипедист до момента встречи с мотоциклистом
4,5: 9 = 0,5 часа время от начала движения мотоциклиста до встречи с велосипедистом (т.е. время за которое мотоциклист проедет 31,5 км)
31,5 : 0,5 = 63 км/ч - скорость мотоциклиста
72-31,5 = 40,5 км - оставшееся расстояние до города В
40,5 : 63 = 0,64 часа - время за которое мотоциклист проедет 40,5км
0,64 * 9 = 5,76 км - расстояние которое проедет велосипедист за это время
31,5+5,76=47,26 (47,3км) - расстояние которое проехал велосипедист за все время движения мотоциклиста
72-47,3 = 24,7 (км) на таком расстоянии от города В будет велосипедист, когда туда приедет мотоциклист

Answer 2

Problem Analysis

We are given that the distance between city A and city B is 72 km. A cyclist leaves city A with a speed of 9 km/h. After 3 hours, a motorcyclist leaves city A and catches up with the cyclist at a distance of 31.5 km from city A. We need to find the distance from city B where the cyclist will be when the motorcyclist arrives.

Solution

Let's break down the problem step by step:

1. Calculate the distance covered by the cyclist in 3 hours. 2. Calculate the remaining distance between the motorcyclist and the cyclist when the motorcyclist catches up. 3. Subtract the remaining distance from the total distance between city A and city B to find the distance from city B where the cyclist will be when the motorcyclist arrives.

Step 1: Calculate the distance covered by the cyclist in 3 hours

The cyclist's speed is 9 km/h, and the time is 3 hours. We can use the formula `distance = speed * time` to calculate the distance covered by the cyclist in 3 hours.

Distance covered by the cyclist in 3 hours: ``` distance_cyclist = 9 km/h * 3 h = 27 km ```

Step 2: Calculate the remaining distance between the motorcyclist and the cyclist when the motorcyclist catches up

The motorcyclist catches up with the cyclist at a distance of 31.5 km from city A. We can subtract the distance covered by the cyclist in 3 hours from this distance to find the remaining distance between the motorcyclist and the cyclist.

Remaining distance between the motorcyclist and the cyclist: ``` remaining_distance = 31.5 km - 27 km = 4.5 km ```

Step 3: Calculate the distance from city B where the cyclist will be when the motorcyclist arrives

The total distance between city A and city B is 72 km. We can subtract the remaining distance between the motorcyclist and the cyclist from this total distance to find the distance from city B where the cyclist will be when the motorcyclist arrives.

Distance from city B where the cyclist will be when the motorcyclist arrives: ``` distance_from_B = 72 km - 4.5 km = 67.5 km ```

Answer

The cyclist will be at a distance of 67.5 km from city B when the motorcyclist arrives.