Two lighthouse beams, A and B, both flash at the same time.
Beam A flashes every 15 minutes.
Beam B flashes every 18 minutes.
Both beams flash together at 9:45 am.
At what time will both beams next flash together?
59 exam-style questions on Edexcel GCSE Maths Prime Factors, HCF and LCM. Each one has a worked solution and a mark scheme showing where the marks go.