Runner A completes a lap of a track every 45 seconds.
Runner B completes a lap of the same track every 60 seconds.
They both start a lap at the same time from the start line.
Work out how many seconds it will take for both runners to cross the start line at the same time again.
58 exam-style questions on AQA GCSE Maths Prime Factors, HCF and LCM. Each one has a worked solution and a mark scheme showing where the marks go.