Let the n numbers be a1, a2, a3, ...., an.

Then the average would be (a1+a2+...+an)/n = p

The mean of a1 and a2 is q. That is (a1+a2)/2 = q. So how much is a1+a2

The remaining numbers have a mean of (a3+a4+...+an)/(n-2) = 10. How much is a3+a4+...+an?

Continue from here. 1st find out what a1+a2+...an equals in terms of n, p and q.