calculate number of trays

For a tray tower with 55% tray efficiency, calculate the required number of trays using engineering paper with the graph paper attached for the following problem: 200kgmole/h of air containing 1 mole\% methanol enters an absorption column. Air leaving the column contains 0.1% methanol. Pure water enters the absorption column at a rate of 150kgmole/h. The entire column operates at 59.4oC. The equilibrium relationship for methanol is: y=0.58x