You have piano lessons every fifth day and cooking classes every sixth day. Today you have both lessons. In how many days will you have both lessons on the same day again?
Start off with a chart (you don't really need to but it helps) Piano lessons 5,10,15,20,25,30 Cooking Classes 6,12,18,24,30 every 30 days, you have both lessons so you will have them on the 60th day