Question

первый участок пути мотоциклист ехал со скоростью 42 км\ч, а второй- со скоростью 30 км\ч. всего он проехал 129 км. за сколько времени мотоциклист проехал первый участок пути и засколько второй, если на первый участок пути он затратил на 0,5 ч меньше, чем на второй?

Answer 1

Х ч. - затратил мотоциклист на 1-ый участок
у ч. - затратил на 2-ой участок
Составляем систему ур-ний:
у-х=0,5
42х+30у=129
Выражаем у через х
у=0,5+х
Подставляем х во 2-ое ур-ние
42х+30(0,5+х)=129
72х=129-15
72х=114
х=1 7/12ч.=1ч 35мин - проехал мотоциклист 1-ый участок
0,5ч=30мин
у=30 мин+1ч35мин=2ч 05 мин - затратил мотоциклист на 2-ой участок
или
у=1 7/12+ 5/10=19/12+5/10=125/60=2 1/12 ч=2ч.5 мин

Answer 2

Problem Analysis

To solve this problem, we need to find the time it took for the motorcyclist to travel the first and second segments of the journey. We are given the speeds of the two segments, the total distance traveled, and the time difference between the two segments.

Solution

Let's denote: - s1 as the speed of the first segment (42 km/h) - s2 as the speed of the second segment (30 km/h) - d as the total distance traveled (129 km) - t1 as the time taken for the first segment - t2 as the time taken for the second segment

We know that the time taken for the first segment is 0.5 hours less than the time taken for the second segment.

We can use the formula: time = distance / speed to calculate the time taken for each segment.

Calculations

Using the given information, we can calculate the time taken for each segment.

For the first segment: t1 = d1 / s1

For the second segment: t2 = d2 / s2

We also know that t1 = t2 - 0.5

Substitution

Substituting the values of t1 and t2 into the equations, we can solve for the time taken for each segment.

Final Steps

After finding the time taken for each segment, we can present the final answers.

Let's proceed with the calculations.