8 M" z- w4 i9 Y公仔箱論壇each time 4 person but 1 need to back to pick up the other 3 7 h: p: a) C/ Y! Ureturn x 10 = 30 people$ e8 X7 C$ a& s P( z2 N' j6 U
1 time return 9 l' |) o, e/ I2 [+ R2 person on last time 公仔箱論壇1 V- b) t) a. v# j5 D% _" N. L
total : 12 times