Question

За 12 секунд участник школьных соревнований пробежал 60 м. а) если он будет бежать с той же скоростью, то за сколько секунд он пробежит 40 м? 100м? б) за какое время пробежит 200м спортсмен , скорость которого в 2 раза больше?

Answer 1

Найдем скорость:v = s/t = 60/12 = 5м/с.
а) Тогда 40 метров он пробежит за: 40/5 = 8 с 
         100 метров он пробежит за: 100/5= 20 с.
б) Удвоенная скорость: 2*5 = 10 м/с.Тогда 200 м он пробежит за 200/10 = 20 с.

Answer 2

Problem Analysis

We are given that a participant in a school competition ran 60 meters in 12 seconds. We need to determine how long it will take for the participant to run 40 meters and 100 meters at the same speed. Additionally, we need to find the time it takes for a different participant, whose speed is twice as fast, to run 200 meters.

Solution

Let's solve each part of the problem step by step.

a) To find the time it takes for the participant to run 40 meters, we can set up a proportion using the ratio of distance to time. Since the participant's speed remains the same, the ratio of distance to time will be constant.

Let's set up the proportion:

60 meters / 12 seconds = 40 meters / x seconds

To solve for x, we can cross-multiply and then divide:

60 * x = 12 * 40
x = (12 * 40) / 60

Simplifying the expression:

x = 8 seconds

Therefore, it will take the participant 8 seconds to run 40 meters.

Now, let's find the time it takes for the participant to run 100 meters. We can use the same approach:

60 meters / 12 seconds = 100 meters / x seconds

Cross-multiplying and solving for x:

60 * x = 12 * 100
x = (12 * 100) / 60

Simplifying the expression:

x = 20 seconds

Therefore, it will take the participant 20 seconds to run 100 meters.

b) Now, let's find the time it takes for a participant, whose speed is twice as fast, to run 200 meters. Since the speed is twice as fast, the time taken will be half of the original time.

Let's set up the proportion:

60 meters / 12 seconds = 200 meters / x seconds

Cross-multiplying and solving for x:

60 * x = 12 * 200
x = (12 * 200) / 60

Simplifying the expression:

x = 40 seconds

Therefore, it will take the participant, whose speed is twice as fast, 40 seconds to run 200 meters.

Summary

To summarize the results: a) The participant will take 8 seconds to run 40 meters and 20 seconds to run 100 meters at the same speed. b) The participant, whose speed is twice as fast, will take 40 seconds to run 200 meters.

Please let me know if I can help you with anything else.