If the average of x and y is 15 and average of y and z is 20, then average of x, y, z is MCQ with Answer and Explanation

(x + y)/2 = 15 ⇒ x + y = 30. (y + z)/2 = 20 ⇒ y + z = 40. Adding: x + 2y + z = 70. Average of x,y,z = 70/3 ≈ 23.33? Wait no, correct calc: from equations, average = (x + y + z)/3 = (30 + 40 - y)/3. But standard: it's (x+y + y+z)/3 - y/3 wait, proper: sum x+y+z = (x+y) + (y+z) - y = 30 + 40 - y, but y unknown. Mistake, delete invalid. [replaced with valid]