Question

A bus heading to Belfast leaves Antrim every 36 minutes.

A bus heading to Ballymena leaves Antrim every 45 minutes
At 10am bus to Belfast and a bus to Ballymena both leave Antrim Bus Station.
Work out the next time that both buses leave at the same time.

Answer 1

• At 1 PM

Explanation:

The leaving intervals are 36 and 45 minutes.

To find out the next time, first find the LCM of the two numbers.

Factorize each:

• 36 = 2*2*3*3
• 45 = 3*3*5

Find the LCM:

• LCM(36, 45) = 2*2*3*3*5 = 180 minutes = 3 hours

Add 3 hours to 10 AM:

• 10 AM + 3 hours = 1 PM