圖片參考：http://imgcld.yimg.com/8/n/HA00329102/o/701109250010513875240280.jpg
can anyone help me to solve the maths?
更新1:
http://fapomatic.com/u1/611/fb47ce2eb427e3636da27673ff795f08/.png
更新2:
the above is the clear version...
