Question

Гульмира вышла из дома на скорости 63 км / ч. Через 120 минут на скорости 88 км / ч вышел Усен. Через сколько часов расстояние между экватором составит 21 км?

Answer 1

Ответ:

1) 63 · 2 = 126 (км) - проедет Гульмира за 2 часа;

2) 88 - 63 = 25 (км/ч) - скорость сближения при движении вдогонку;

3) 126 - 21 = 105 (км) - расстояние, которое надо проехать;

4) 105 : 25 = 4,2 (ч) - время в пути.

4,2 ч = 4 ч + (0,2 · 60) мин = 4 ч 12 мин

Ответ: через 4 часа 12 минут после выезда Усена.

Проверка:

63 · (2 + 4,2) = 390,6 км - проедет Гульмира за 6,2 ч;

88 · 4,2 = 369,6 км - проедет Усен за 4,2 ч;

390,6 - 369,6 = 21 км - расстояние между ними через 4,2 ч.

Answer 2

Calculation of Time for Distance between Gulmira and Usen to be 21 km

To calculate the time it takes for the distance between Gulmira and Usen to be 21 km, we need to determine the time it takes for each person to cover that distance at their respective speeds.

Given information: - Gulmira's speed: 63 km/h - Usen's speed: 88 km/h

Let's calculate the time it takes for Gulmira and Usen to cover the distance of 21 km individually.

Time taken by Gulmira: - Distance: 21 km - Speed: 63 km/h - Time = Distance / Speed = 21 km / 63 km/h = 0.333 hours

Time taken by Usen: - Distance: 21 km - Speed: 88 km/h - Time = Distance / Speed = 21 km / 88 km/h = 0.239 hours

Now, we need to find the time it takes for both Gulmira and Usen to cover the distance of 21 km together. Since they started at different times, we need to consider the time difference between them.

Given information: - Gulmira started 120 minutes (2 hours) before Usen.

To find the total time, we add the time taken by Gulmira and the time difference between them.

Total time taken: - Time taken by Gulmira: 0.333 hours - Time difference: 2 hours - Total time = Time taken by Gulmira + Time difference = 0.333 hours + 2 hours = 2.333 hours

Therefore, the distance between Gulmira and Usen will be 21 km after approximately 2.333 hours.

Please note that this calculation assumes a constant speed throughout the entire journey for both Gulmira and Usen.