Three lighthouses flash their lights at intervals of 6 seconds, 9 seconds and 15 seconds respectively. They all flash together at 8:00 a.m. At what time will they next flash all together?
FREE QUIZ · PRIMARY 4 MATHEMATICS
Factors and Multiples
Five MCQs on Factors and Multiples. Pick an answer, see the specific misconception. The diagnosis comes after the score.
Two boxes of cookies contain 84 and 126 cookies respectively. The cookies from BOTH boxes are to be packed into identical small bags such that each bag has the same number of cookies, and the bags use up ALL the cookies (no leftovers). What is the GREATEST number of cookies per bag?
Three friends ride bicycles around a circular track in Singapore. Olivia completes one lap every 3 minutes, Stan completes one lap every 4 minutes, and Sara completes one lap every 6 minutes. They all start together at the start line. After how many minutes will they ALL be at the start line together for the FIRST time after starting?
What is the SMALLEST 3-digit number that is a common multiple of 6 and 9?
Find the smallest common multiple of 6 and 8.