There are 4 consecutive odd numbers `(x_1,\ x_2,\ x_3\ a n d\ x_4)` and three consecutive even numbers (`y_1,\ y_2\ a n d\ y_3)` . The average of the odd numbers is 6 less than the average of the even numbers. If the sum of the three even numbers is 16 less than the sum of the four odd numbers, what is the average of `x_1,\ x_2,\ x_3` and `x_4` ? (a) 30 (b) 38 (c) 32 (d) 34