Question

7класс алгебра Турист выехал на велосипеде из дома отдыха, расположенного на берегу реки Кок-су, и направился в соседний дом отдыха, намереваясь доехать туда за некоторое время. Сначала он за 1 час проехал 10,5км. Если бы он и дальше ехал такой же скоростью, то прибыл бы на место назначения на 1 час позднее. Поэтому он оставшийся путь проехал со скоростью 15км/ч и прибыл на место назначения на пол часа раньше. Найти расстояние между домами отдыха. даю 20 баллов, ребят пж решите пример

Answer 1

Пусть расстояние будет х км
х\10,5- время затраченное на путь со скоростью-10,5км\час
х\15-время ,затр на путь со скор 15 км\час
х/10,5=х/15+4
х\10,5-х\15=4
приводим к общему знаменателю
15х-10,5х/157,5=4
4,5х=157,5.х4
4,5х=630
х=630\4,5
х=140км -расстояние

Answer 2

Problem Analysis

The problem involves a cyclist traveling from one riverside rest house to another. The cyclist initially travels at a certain speed for a specific distance and then adjusts their speed for the remaining distance. We need to find the distance between the two rest houses.

Solution

Let's denote the total distance between the rest houses as D. The cyclist's initial speed is v1 and the remaining distance is covered at a speed of v2.

The time taken to cover the initial distance at speed v1 is t1, and the time taken to cover the remaining distance at speed v2 is t2.

We are given the following information: 1. The cyclist initially travels at a speed of 10.5 km/h for 1 hour. 2. If the cyclist had continued at the same speed, they would have arrived 1 hour late. 3. The cyclist covers the remaining distance at a speed of 15 km/h and arrives 30 minutes early.

Calculations

We can use the following equations to solve for the distance D: 1. t1 = initial distance / v1 2. t2 = remaining distance / v2 3. t1 + t2 = total time taken 4. t1 - 1 = t2 + 0.5 (1 hour late and 30 minutes early)

Let's solve for D using the given information.

Solution Steps

1. Calculate the time taken to cover the initial distance and the remaining distance. 2. Use the time equations to solve for the total distance D.

Solution

The distance between the two rest houses is 63 km.

I hope this helps! If you have further questions, feel free to ask.