Hex #40c300 or rgb(64,195,0) in RGB space is the tint of grass green. It has hue angle of 100.31 degrees, value = 76 and saturation = 100. #40c300 can be obtained by mixing 2 colors: 1 drop of yellow, 3 drops of green.
Nearest safe hex - #33cc00. Below you can see the block with #40c300 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #40c300 to the mixer and play with it.