Someone, please help my test ends in 15 min

Acertain standardized? test's math scores have a? bell-shaped distribution with a mean of 520 and a standard deviation of 105. complete parts? (a) through? (c)

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?