The mean of two numbers x and y is 4. Find the mean of four numbers x, 2x, y and 2y

The mean of two numbers x and y is 4, which means (x + y) / 2 = 4. Solving for x + y, we get x + y = 8. Now we need to find the mean of four numbers x, 2x, y, and 2y. The mean is calculated by adding up all the numbers and dividing by the total number of numbers. So the sum of these four numbers is x + 2x + y + 2y = 3x + 3y, and the total number of numbers is 4. Therefore, the mean is (3x + 3y) / 4. We can substitute 8 for x + y since we know it equals 8, and simplify the expression to get (3x + 3y) / 4 = (3(x+y)) / 4 = (3(8)) / 4 = 6. Therefore, the mean of the four numbers x, 2x, y, and 2y is 6. The answer is option C.