he diffusion constant for a particular ion crossing an artificial membrane is $2\mathrm{.}90$ x$10-16$ m$2/$s$.$ The membrane has an area of $9\mathrm{.}00$ x$10-15$ m$2.$ On one side of the membrane there is pure water, on the other side there is a $0\mathrm{.}660$ x $103$ mol$/$m$3$ solution of the ions. If $7\mathrm{.}00$ x $104$ ions cross the membrane each second, what is the thickness of the membrane? Answer units of nm $(1$x$10-9$ m$)$ to two decimal places, but do not include units in your answer.$$