If i eat myself will I get twice as big or disappear completely?

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.

Rounded to the nearest tenth, what is the value of x