Scones bake for 15 minutes muffins baked for 12 minutes cookies bake for 10 minutes. When one tray is done he removes it and replace it with another tray of the same how many minutes after he puts the trays in the oven will he first remove the scones, muffins and cookies at the same time.
To find the least common multiple (LCM) of 15, 12, and 10, we can list their multiples:
Multiples of 15: 15, 30, 45, 60, ...
Multiples of 12: 12, 24, 36, 48, 60, ...
Multiples of 10: 10, 20, 30, 40, 50, 60, ...
The first time all three numbers appear in the list is 60. Therefore, the baker will first remove the scones, muffins, and cookies at the same time after 60 minutes.