mercator charts

[Mbasa]

Hi guys am yet to sit exams but i need help with the following questions:

1. On a mercator chart the spacing between meridians 1 degree apart is 2.5cm, what is the scale at 40S?

2. Briefly explain the trend of temperature changes in the troposphere.

3. The following observations were obtained by an aircraft of a VORTAC:
0813z Radial 185 DME 76nm
0825z Radial 230 DME 76nm
TAS 320, heading 292(m), variation 12w.
Determine the ground speed and mean W/V

[Mbasa]

Friends please help me with this;

What is the meridian spacing in cm on a mercator chart?

An aircraft in southern hemispere heading 180 degrees has relative bearing of 210 indicated on the ADF. At the same time the VOR CDI with the left/right needle centralized indicates 315 TO. Deviation 2W, aircraft and both radio facilities is 4n degrees. What bearing would you plot on a mercator chart?

Aircraft heading 325(m) ADF reads 330 relative, Track to intercept 280(m) INBOUND, interception angle 50 degrees. Calculate:
a) The interception heading

b) The alteration of heading

c) The relative bearing at interception