Calculate the LCM of 2, 4, 6, 8, 10, and 12 seconds. The answer will be 120 seconds. Therefore at 2 minutes, it rings once. This means that the bells will ring 15 times in 30 minutes.

Revise how to add, subtract, multiply and divide fractions, how to use a calculator for fractions and how to find fractions of amounts in this GCSE maths guide.

LCM (Least Common Multiple): - The LCM of two or more given numbers is the least number to be exactly divisible by each of them. For instance, we can obtain LCM of 4 and 12 as follows- ...