<s>[INST] Probability of point Q being inside or on the sphere github = 1/2 and same is the probability of point P: @OK, that's a given statement. However, the question reads: "A point P is selected inside or on a sphere of radius 'r'. Then another point Q is selected inside or on same sphere, but it can be same as P. If Q is selected inside or on shell of radius 'R' at distance x from P, then probability of P being inside or on shell of radius R is 1/2. What is average distance between P and Q?[/INST]