Question

A bell rings every 15minutes. Another bell rings every 25minutes they ring together at 12noon at what time will they ring together again

Answer 1

We need to take the LCM of 15 and 25

15 = 3 x 5

25 = 5 x 5

LCM = 3 x 5 x 5 = 75

They ring at 12 noon, and after that they will ring at 1:15 PM

That is exactly after 75 mins