When $1\mathrm{.}0-$C point charge is $15$ m from a second point charge, the force each one experiences a force of $1\mathrm{.}0$N$.$ What is the magnitude of the second charge? $($k $=1/4$$0=9\mathrm{.}0109$ N $$ m$2/$C$2)$

$25$ C$25$ nC$1\mathrm{.}0$ C$0\mathrm{.}025$ C$10$ nC