64seconds0 _& s/ Q9 K6 S6 k4 W' U
6 c) f& G( z; s6 Ptvb now,tvbnow,bttvb1 to 4 have 3floors = 48 sec
: t4 i+ K9 \( r. j1 E8 X/ c- ?avg. 48/3 = 16sec
% N' f/ U8 C; ]3 h; _6 Y9 u; V
9 Y0 Y! z! N6 s% l4 to 8 have 4floors = 16x4公仔箱論壇9 Z# K' C' M4 z6 ?7 p, d
= 64secs |