Help! I am doing a multi-part practice problem in preparation for a midterm I have on Monday. I am able to figure some of the components out but not all of them. Here is the information:

It's a sunny day, and cumulus clouds are forming by convection. Surface conditions are: Temperature=16.4 C, Wet bulb temperature = 10.6 C, Pressure = 102 kPa (Other info: DALR = 1C/100m, MALR 0.6C/100m, TdLR = 0.2C/100m, RH = 100 e/es, Ma = 29 kg/kmol, Mv = 18 kg/kmol, R = 8314 J/K*kmol)

1 - Show that the mixing ration at the surface is about 5 g/kg

(I have established e = 9.064 mb and I know that MR = 0.622e/P but I don't know how to show that this is 5 g/kg)

2. The lower troposphere is unstable, and a parcel of air rises from the surface. Estimate the height above ground of the cloud base in this parcel.

(Dewpoint temp is approx 5.6C using the vapour pressure table but I'm not sure what to do after this).

3. Why can you assume the mixing ration in the parcel at 1km (Pressure = 90.4 kPa) is the same as the value at the surface? Using this assumption, calculate the relative humidity at 1 km in the parcel.

(I'm lost on this one)