Step 1: Calculate the total mass of the aircraft.

 

The question states that the aircraft has a 2 wheel nose gear and they have given you the wheel load for a single wheel of 500kg they also say that the single main wheel load is 6000kg's and you have 4 of those

 

2 x 500 =1000kg load on nose wheel

4 x 6000 = 24000kg load on the rear wheels

Total mass = 25 000kg

 

Step 2 Calculate the moment

 

1000 x 10 = 10 000 Moment of the nose wheel

Assume that the moment for the rear wheels have no moment i.e. factor of 0

 

Step 3 Calculate the arm = moment/mass

10 000/25 000 =0.4m or 40cm