Question

Три велосипедиста начали с общего старта движение по круговой дорожке. Первый делает полный круг за 21 мин, второй-за 35 мин, а третий-за 15 мин. Через сколько минут они еще раз окажутся вместе в начальном пункте?

Answer 1

Через 105 минут. Это число кратно всем трём числам 21, 35 и 15. Первый к этому времени проедет 5 кругов, второй - 3 круга, а третий - 7 кругов.

Answer 2

Problem Analysis

Three cyclists start moving from a common starting point on a circular track. The first cyclist completes a full lap in 21 minutes, the second cyclist completes a full lap in 35 minutes, and the third cyclist completes a full lap in 15 minutes. We need to determine how many minutes it will take for all three cyclists to be together at the starting point again.

Solution

To find the time it takes for all three cyclists to be together at the starting point again, we need to find the least common multiple (LCM) of the three lap times.

The LCM of three numbers can be found by finding the LCM of the first two numbers, and then finding the LCM of that result with the third number.

Let's calculate the LCM of the lap times of the three cyclists