Question

Bus a leaves every 30 mins

bus b leaves every 20 mins
at 10 am both buses leave the station together
work out the next time they will leave at the same time

Answer 1

11 am.

Explanation:

That would be the LCM of 20 and 30 which is 60 minutes.

So the nexrt time will be 10.00 + 60 mins

= 11.00 am.

Answer 2

Explanation:

Find the LCM of 30 & 20

30 = 2 * 5 * 3

20 = 2 * 2 * 5

LCM = 2 * 3 * 2 * 5 = 60

60 minutes = 1 hour

So, again at 10am both will leave at the same time