Question

21) Поезд прошел : часть пути длиной 600 км, после чего он сделал оста- новку на 1 час 30 минут. Чтобы вовремя прибыть на последнюю стан- цию, он увеличил скорость на 15 км/час. Сколько часов поезд находился в пути?

Answer 1

Ответ:

10ч

Пошаговое объяснение:

600*1/4=150км было пройдено

600-150=450км осталость

хкм/ч скорость по плану,время 450/хч

х+15км/ч-двигался 450км.время 450/(х+15)ч

450/х-450/(х+15)=1,5

1,5х(х+15)-450*(х+15-х)=0

1,5х²+22,5х-6750=0

х²+15х-4500=0

D=225+18000=18225

√D=135

x1=(-15-135)/2=-75 не удов усл

х2=(-15+135)/2=60км/ ч по плану

60+15=75км/ч скорость на пути 450км

450:75=6ч ехал после остановки

150:60=2,5ч ехал до остановки

6+2,5+1,5=10ч поезд был в пути

или

600:60=10ч так как он прибыл во время

Answer 2

Calculation of the Total Time the Train Spent on the Journey

To calculate the total time the train spent on the journey, we need to consider the distance traveled before the stop and the increased speed after the stop.

Let's break down the information given:

- The train traveled a distance of 600 km before making a stop. - The duration of the stop was 1 hour and 30 minutes. - After the stop, the train increased its speed by 15 km/h.

To calculate the time spent on the journey, we need to consider the time taken to cover the initial distance and the time taken to cover the additional distance at the increased speed.

Time taken to cover the initial distance

The time taken to cover a distance can be calculated using the formula:

Time = Distance / Speed

For the initial distance of 600 km, we need to determine the time taken at the original speed.

Time taken to cover the additional distance

After the stop, the train increased its speed by 15 km/h. We need to determine the additional distance covered and calculate the time taken at the increased speed.

Calculation Steps

1. Calculate the time taken to cover the initial distance of 600 km at the original speed. 2. Calculate the additional distance covered after the stop. 3. Calculate the time taken to cover the additional distance at the increased speed. 4. Add the times calculated in steps 1 and 3 to get the total time spent on the journey.

Let's perform the calculations:

1. Time taken to cover the initial distance: - Distance: 600 km - Speed: Original speed (not provided in the question) - Time = Distance / Speed

2. Additional distance covered after the stop: - Speed increased by 15 km/h - Duration of the stop: 1 hour and 30 minutes - Additional distance = Speed * Time

3. Time taken to cover the additional distance: - Distance: Additional distance calculated in step 2 - Speed: Increased speed (original speed + 15 km/h) - Time = Distance / Speed

4. Total time spent on the journey: - Total time = Time taken to cover the initial distance + Time taken to cover the additional distance

Please provide the original speed of the train so that we can proceed with the calculations.