The answer is 91公仔箱論壇4 R/ j* G' H! W" S' E/ P
1 row 3x4+1x3=15
; h+ [# {, H5 K( E1 `8 v2 row 4x5+2x4=28
' Y" g+ g) M' Qtvb now,tvbnow,bttvb3 row 5x6+3x5=45
; `6 n% h1 `% w5 C公仔箱論壇4 row 6x7+4x6=66tvb now,tvbnow,bttvb/ p J2 ]2 U2 F* L' }8 o( m5 C
5 row 7x8+5x7=91  |