Questions

First weigh 3 against 3 balls. If the ball contains among these six balls, then take the three balls which weighed over, and weigh the ball 1 against 1. If the balls are not equal and any one of the ball weighs more, that is the overweight ball, else the one among the three which is not weighed is the ball. If the 3 against 3 balls were equal, then weigh the 2 balls, then the overweight ball will be found.

Yes, footsteps are what we take more, the more we leave behind. 

Mixing of blue and yellow colors make Green Color.

RYB (an abbreviation of red–yellow–blue) is a historical set of colors used in subtractive color mixing and is one commonly used set of primary colors. It is primarily used in art and design education, particularly painting.

RYB predates modern scientific color theory, which has determined that cyan, magenta, and yellow are the best set of three colorants to combine, for the widest range of high-chroma colors.