Two hosts, A and B$,$ connected by a single link of rate $56$kbps$.$ Suppose thay the two hosts are separated by m meters, and the propagation speed along the link is $2\mathrm{.}5*10$ m$/$s$.$ If host A is to send a packet of $120$ bits to B$,$ find the distance m so that the propagation delay equals to the transmission delay.