**1)**** Consider a soil sample that has three layers. The value of permeability of the second layer is twice that of the first layer & the value of permeability of the third layer is thrice that of the first layer. The depth of each layer is the same, i.e., 5m. **

**Find the average value of permeability parallel to the bedding plane? **

- a) k
- b) 2k
- c) 3k
- d) 4k

**Answer: b) 2k**

Explanation:Let 〖 K〗_1, 〖 K〗_2 & 〖 K〗_3 be the values of permeability of the three layers.

From the above numerical,

〖 K〗_1= k

〖 K〗_2 = 2k

〖 K〗_3 = 3k

〖 Z〗_1 = 〖 Z〗_2 = 〖 Z〗_3=5mWhen the flow is parallel to the bedding plane, then the coefficient of permeability is,

K = ( 〖 K〗_1 Z_1+ K_2 Z_2+⋯+K_n Z_n)/Z

K = (5k+10k+15k)/15k

K = 2k

Hence the average value of permeability parallel to the bedding plane is twice the first layer’s permeability.