[单选题]
A swimmer heading directp2ok:i0 2 m vefp97killy across a riveb73bly*i+;(l tjjk ixozaw( m) d )v6vr 200 m wide reaches the opposite bank in 6 min 40 s. Shebx+v) *j;6vw lk7jml)(a3zi b(t idyo is swept downstream 480 m. What is the speed of the current?