Question

3. There are two city buses in Saratoga. Bus A completes its route in 25 minutes. Bus B completes its route in 40 minutes. Both of their routes end at the bus station. If both buses leave the bus station at the same time in the morning, how many minutes will pass before the two buses meet at the train station?

Answer 1

To find the answer, we have to find the LCM of 25 and 40.

To get LCM, we

Write each number as prime factors

take the prime factor that occurs greatest number of time

take the product of those

Thus,

25 = 5 * 5

40 = 2 * 2 * 2 * 5

2 occurs 3 times and 5 occurs 2 times (greatest).

hence,

LCM(25, 40) = 2 * 2 * 2 * 5 * 5 = 200

So,

200 mins will pass before the two buses meet