11. An advertisement board displays letters in green-coloured lights and pictures in yellow-coloured lights. The green lights come on every 10 seconds and the yellow lights come on every 15 seconds. If both the lights are turned on at the same time, after how many seconds will they come on together again?

11. An advertisement board displays letters in green-coloured lights a

1.	11. An advertisement board displays letters in green-coloured lights and pictures in yellow-coloured lights. The green lights come on every 10 seconds and the yellow lights come on every 15 seconds. If both the lights are turned on at the same time, after how many seconds will they come on together again?
Answer» 30 SEC afterStep-by-step EXPLANATION:LCM of 15 and 10 = 5X2X3=30