This might sound stupid,but does anyone know how long it takes to boil a perfect egg? Thanks.

this might sound stupid,but does anyone know how long it takes to boil a perfect egg? thanks.
Not how long but how: put the egg in cold water(tap ) when the water start to boil remove the heat.let it sit in the water for 20 min; it fully cook

Here is a quick, easy, and no-discolored-yolk way to hard boil eggs...

-Place Large eggs in a heavy bottomed pan.
-Cover with 1" of cold water and cover pan with a lid.
-Bring water to a boil watch carefully because the timing starts when it boils.
-Turn off the heat and keep pan covered for exactly 10 minutes. (X-Large eggs will take 2-3 minutes longer)
-Cool eggs by rinsing with very cold water or submerge in iced water to stop the cooking process.
FYI:
-Older eggs peel much easier than fresh eggs.
-If you are unsure if an uncooked egg is too old or not, place it in a cup of water. If the egg floats, at the top of the glass, get rid of it.
-A hard boiled egg that is still in the shell will spin on a counter, but you can't spin an uncooked egg. Hope that helps!