Question

Three bulbs of different colours are glowing as follows:
Red bulb glows after every 15 seconds.
Blue bulb glows after every 10 seconds
and yellow bulb glows after every 8 seconds.
How many times will the three bulbs glow together per every 24 hours ​

Answer 1

red bulb glows = 15 seconds

blue bulb glows = 10 seconds

yellow bulb glows = 8 second

times 3 bulbs glows = take LCM of 15,10,8

LCM of 3 bulbs are 120 seconds

in every 24 hours bulb will glow = 24x60x60 = 2880 seconds

red bulb =

$\frac{2880}{15} = 192$

blue bulb =

$\frac{2880}{10} = 288$

yellow bulb=

$\frac{2880}{8} = 360$