Alarm X sounds every 15 seconds.
Alarm Y sounds every 20 seconds.
Alarm Z sounds every 25 seconds.
All three alarms sound at the same time.
Work out how long it will take for all three alarms to sound at the same time again.
Practise OCR GCSE Maths Prime Factors, HCF and LCM with exam-style questions for Foundation and Higher tier. 59 questions, matched to the OCR GCSE Maths (J560) specification and written in the written papers style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.