$($b$)$ What pressure difference must be maintained along each kilometer of the pipe to maintain this flow rate? $(2\mathrm{.}5$pt$)$

Important info : Gasoline is piped underground from refineries to major users. The flow rate is $3\mathrm{.}00$ x$10^-2$ m$^3/$s $($about $500$ gal$/$min$),$the viscosity of gasoline is $1\mathrm{.}00$x$10^-3($N$/$m$^2)$s$,$ and its density is $680$ kg$/$m$^3.$ If Reynolds number is to be less than $2000=$ diameter is less than or equal to $0\mathrm{.}13$m