I need some help on this...

1. Rhombus MNOP is inscribed in rectangle WXYZ such that M, N, O, P lie on WX, XY, YZ, ZW respectively. If MX=15, XN=20, MO=30, NP=40. a/b a simplified fraction which represent the area of WXYZ. Find a+b. What is the area of rectangle WXYZ (express in fraction.)