64) If x, y, z are three numbers between 2 and 18 such that:

(i) their sum is 25,

(ii) the numbers 2, x, y are consecutive terms of an A.P., and

(iii) the numbers y, z, 18 are consecutive terms of a G.P., then those numbers are

123) a, b, x, y are positive numbers such that a, x, b are in A.P. and a, y, b are in G.P. and z = (2ab)/(a + b), then: