Question

It is Maggie, Kate and Sam's sports day. They all have participated in a race. All of them run around a circular track and they complete 1 revolution in 2, 4 and 6 hours respectively. When will they all meet at the starting point?

• A. After 8 hours
• B. After 12 hours
• C. After 6 hours
• D. After 4 hours

Answer 1

The correct option is B After 12 hours

They all will meet at the starting point after completing their respective revolutions. As we can see that Maggie takes 2 hours to complete 1 revolution, Kate takes 4 hours and Sam takes 6 hours. We have to find a common multiple of these numbers to know the time of their meeting at the starting point. If we calculate the LCM (least common multiple) of 2, 4 and 6, the result obtained is 12. Therefore, they will meet the starting point after 12 hours.

So, the LCM is 2 × 2 × 3 = 12